When certain substances are added to diet cola, CO₂ gas is produced, generating a foam. Two experiments were done to study this process. In each trial, an apparatus like that shown in Figure 1 was used as follows: A jar was nearly filled with H₂O and fitted with a 2-holed lid. One end of a tube (Tube B) was inserted through one of the holes and submerged. The other end of Tube B was placed in an empty graduated cylinder. Another tube (Tube A) was inserted through the other hole in the lid. A certain solid substance was inserted into the other end of Tube A, and the substance was secured by a clamp. Tube A was then attached to a freshly opened bottle containing 355 mL of diet cola. The clamp was removed, releasing the substance into the diet cola. The foam that was produced travelled into the jar, and liquid was transferred into the cylinder. The mass of CO₂ produced was calculated based on the volume of liquid that was measured in the cylinder after foaming had ceased.

Experiment 1

In each of Trials 1−4, a different 1 of 4 substances of equal mass—a piece of chalk, a sugar cube, a fruit-flavored piece of candy, or a mint-flavored piece of candy—was added to a bottle of diet cola at 3°C. See Table 1.

Experiment 2

In each of Trials 5−8, Trial 4 from Experiment 1 was repeated, except that the temperature of the diet cola was different in each trial. See Table 2.

According to Figure 1, which of Tube A and Tube B, if either, had at least one end submerged in a liquid before the clamp was removed?

When certain substances are added to diet cola, CO₂ gas is produced, generating a foam. Two experiments were done to study this process. In each trial, an apparatus like that shown in Figure 1 was used as follows: A jar was nearly filled with H₂O and fitted with a 2-holed lid. One end of a tube (Tube B) was inserted through one of the holes and submerged. The other end of Tube B was placed in an empty graduated cylinder. Another tube (Tube A) was inserted through the other hole in the lid. A certain solid substance was inserted into the other end of Tube A, and the substance was secured by a clamp. Tube A was then attached to a freshly opened bottle containing 355 mL of diet cola. The clamp was removed, releasing the substance into the diet cola. The foam that was produced travelled into the jar, and liquid was transferred into the cylinder. The mass of CO₂ produced was calculated based on the volume of liquid that was measured in the cylinder after foaming had ceased.

Experiment 1

In each of Trials 1−4, a different 1 of 4 substances of equal mass—a piece of chalk, a sugar cube, a fruit-flavored piece of candy, or a mint-flavored piece of candy—was added to a bottle of diet cola at 3°C. See Table 1.

Experiment 2

In each of Trials 5−8, Trial 4 from Experiment 1 was repeated, except that the temperature of the diet cola was different in each trial. See Table 2.

One millimole (mmol) of CO₂ has a mass of 0.044 g. How many trials resulted in the production of at least 1 mmol of CO₂?

When certain substances are added to diet cola, CO₂ gas is produced, generating a foam. Two experiments were done to study this process. In each trial, an apparatus like that shown in Figure 1 was used as follows: A jar was nearly filled with H₂O and fitted with a 2-holed lid. One end of a tube (Tube B) was inserted through one of the holes and submerged. The other end of Tube B was placed in an empty graduated cylinder. Another tube (Tube A) was inserted through the other hole in the lid. A certain solid substance was inserted into the other end of Tube A, and the substance was secured by a clamp. Tube A was then attached to a freshly opened bottle containing 355 mL of diet cola. The clamp was removed, releasing the substance into the diet cola. The foam that was produced travelled into the jar, and liquid was transferred into the cylinder. The mass of CO₂ produced was calculated based on the volume of liquid that was measured in the cylinder after foaming had ceased.

Experiment 1

In each of Trials 1−4, a different 1 of 4 substances of equal mass—a piece of chalk, a sugar cube, a fruit-flavored piece of candy, or a mint-flavored piece of candy—was added to a bottle of diet cola at 3°C. See Table 1.

Experiment 2

In each of Trials 5−8, Trial 4 from Experiment 1 was repeated, except that the temperature of the diet cola was different in each trial. See Table 2.

Suppose Trial 6 had been repeated, but the bottle of diet cola had been opened and then left undisturbed at 25°C for 12 hours before it was attached to the apparatus. Would the mass of CO₂ produced in this trial likely be greater than 0.969 g or less than 0.969 g?

When certain substances are added to diet cola, CO₂ gas is produced, generating a foam. Two experiments were done to study this process. In each trial, an apparatus like that shown in Figure 1 was used as follows: A jar was nearly filled with H₂O and fitted with a 2-holed lid. One end of a tube (Tube B) was inserted through one of the holes and submerged. The other end of Tube B was placed in an empty graduated cylinder. Another tube (Tube A) was inserted through the other hole in the lid. A certain solid substance was inserted into the other end of Tube A, and the substance was secured by a clamp. Tube A was then attached to a freshly opened bottle containing 355 mL of diet cola. The clamp was removed, releasing the substance into the diet cola. The foam that was produced travelled into the jar, and liquid was transferred into the cylinder. The mass of CO₂ produced was calculated based on the volume of liquid that was measured in the cylinder after foaming had ceased.

Experiment 1

In each of Trials 1−4, a different 1 of 4 substances of equal mass—a piece of chalk, a sugar cube, a fruit-flavored piece of candy, or a mint-flavored piece of candy—was added to a bottle of diet cola at 3°C. See Table 1.

Experiment 2

In each of Trials 5−8, Trial 4 from Experiment 1 was repeated, except that the temperature of the diet cola was different in each trial. See Table 2.

If another trial had been performed in Experiment 2 and 450 mL of liquid had been measured in the cylinder, the temperature of the diet cola in this trial would most likely have been:

In a particular playa (relatively flat, dry desert basin) evidence shows that some large rocks have moved along the surface, leaving shallow trails in the clay sediment, some up to several hundred meters long. Three scientists provided explanations for how these rocks moved.
Scientist 1
In the spring, snowmelt from surrounding mountains runs downhill and collects in the playa. At night, cold temperatures cause this water to freeze around the rocks. When temperatures rise again, the ice begins to melt, leaving a layer of mud on the surface and ice “rafts” around the rocks. The buoyancy of the ice rafts floats the rocks on top of the mud such that even light winds can then push the rocks along the surface. Evidence of this lifting is seen in that the trails left by rocks are both shallow and only about 2/3 as wide as the rocks themselves. Due to the combination of ice, mud, and light winds, the rocks are able to move several hundred meters in a few days.
Scientist 2
Snowmelt from surrounding mountains does collect in the playa during the spring. However, the temperature in the playa does not get cold enough for ice to form. When the playa’s surface gets wet, the top layer of clay transforms into a slick, muddy film. In addition, dormant algae present in the dry clay begin to grow rapidly when the clay becomes wet. The presence of mud and algae reduces friction between the rocks and the clay. Even so, relatively strong winds are required to push the rocks along the wet surface, forming trails. Due to the combination of mud, algae, and strong winds, the rocks are able to move several hundred meters in a few hours.
Scientist 3
Water does collect in the playa, producing mud and ice. However, neither mud nor ice is responsible for the rocks’ movements. The playa is located along a fault line between tectonic plates. Minor vertical shifts in the plates cause the rocks to move downhill, leaving trails. Due to the combination of tectonic plate movement and strong winds, the rocks are able to move only a few meters over several years.

Suppose it were discovered that a particular rock formed a 200 m long trail in 72 hr. Would this discovery support Scientist 1’s explanation?

In a particular playa (relatively flat, dry desert basin) evidence shows that some large rocks have moved along the surface, leaving shallow trails in the clay sediment, some up to several hundred meters long. Three scientists provided explanations for how these rocks moved.

Scientist 1

In the spring, snowmelt from surrounding mountains runs downhill and collects in the playa. At night, cold temperatures cause this water to freeze around the rocks. When temperatures rise again, the ice begins to melt, leaving a layer of mud on the surface and ice “rafts” around the rocks. The buoyancy of the ice rafts floats the rocks on top of the mud such that even light winds can then push the rocks along the surface. Evidence of this lifting is seen in that the trails left by rocks are both shallow and only about 2/3 as wide as the rocks themselves. Due to the combination of ice, mud, and light winds, the rocks are able to move several hundred meters in a few days.

Scientist 2

Snowmelt from surrounding mountains does collect in the playa during the spring. However, the temperature in the playa does not get cold enough for ice to form. When the playa’s surface gets wet, the top layer of clay transforms into a slick, muddy film. In addition, dormant algae present in the dry clay begin to grow rapidly when the clay becomes wet. The presence of mud and algae reduces friction between the rocks and the clay. Even so, relatively strong winds are required to push the rocks along the wet surface, forming trails. Due to the combination of mud, algae, and strong winds, the rocks are able to move several hundred meters in a few hours.

Scientist 3

Water does collect in the playa, producing mud and ice. However, neither mud nor ice is responsible for the rocks’ movements. The playa is located along a fault line between tectonic plates. Minor vertical shifts in the plates cause the rocks to move downhill, leaving trails. Due to the combination of tectonic plate movement and strong winds, the rocks are able to move only a few meters over several years.

Suppose that no seismic activity was recorded in the playa where the trails left by the rocks are found. This finding would weaken which of the scientists’ explanations?

In a particular playa (relatively flat, dry desert basin) evidence shows that some large rocks have moved along the surface, leaving shallow trails in the clay sediment, some up to several hundred meters long. Three scientists provided explanations for how these rocks moved.

Scientist 1

In the spring, snowmelt from surrounding mountains runs downhill and collects in the playa. At night, cold temperatures cause this water to freeze around the rocks. When temperatures rise again, the ice begins to melt, leaving a layer of mud on the surface and ice “rafts” around the rocks. The buoyancy of the ice rafts floats the rocks on top of the mud such that even light winds can then push the rocks along the surface. Evidence of this lifting is seen in that the trails left by rocks are both shallow and only about 2/3 as wide as the rocks themselves. Due to the combination of ice, mud, and light winds, the rocks are able to move several hundred meters in a few days.

Scientist 2

Snowmelt from surrounding mountains does collect in the playa during the spring. However, the temperature in the playa does not get cold enough for ice to form. When the playa’s surface gets wet, the top layer of clay transforms into a slick, muddy film. In addition, dormant algae present in the dry clay begin to grow rapidly when the clay becomes wet. The presence of mud and algae reduces friction between the rocks and the clay. Even so, relatively strong winds are required to push the rocks along the wet surface, forming trails. Due to the combination of mud, algae, and strong winds, the rocks are able to move several hundred meters in a few hours.

Scientist 3

Water does collect in the playa, producing mud and ice. However, neither mud nor ice is responsible for the rocks’ movements. The playa is located along a fault line between tectonic plates. Minor vertical shifts in the plates cause the rocks to move downhill, leaving trails. Due to the combination of tectonic plate movement and strong winds, the rocks are able to move only a few meters over several years.

Suppose a researcher observed that wind speeds greater than 80 miles per hour are needed to move the rocks in the playa. This observation is consistent with which of the scientists’ explanations?

In a particular playa (relatively flat, dry desert basin) evidence shows that some large rocks have moved along the surface, leaving shallow trails in the clay sediment, some up to several hundred meters long. Three scientists provided explanations for how these rocks moved.

Scientist 1

In the spring, snowmelt from surrounding mountains runs downhill and collects in the playa. At night, cold temperatures cause this water to freeze around the rocks. When temperatures rise again, the ice begins to melt, leaving a layer of mud on the surface and ice “rafts” around the rocks. The buoyancy of the ice rafts floats the rocks on top of the mud such that even light winds can then push the rocks along the surface. Evidence of this lifting is seen in that the trails left by rocks are both shallow and only about 2/3 as wide as the rocks themselves. Due to the combination of ice, mud, and light winds, the rocks are able to move several hundred meters in a few days.

Scientist 2

Snowmelt from surrounding mountains does collect in the playa during the spring. However, the temperature in the playa does not get cold enough for ice to form. When the playa’s surface gets wet, the top layer of clay transforms into a slick, muddy film. In addition, dormant algae present in the dry clay begin to grow rapidly when the clay becomes wet. The presence of mud and algae reduces friction between the rocks and the clay. Even so, relatively strong winds are required to push the rocks along the wet surface, forming trails. Due to the combination of mud, algae, and strong winds, the rocks are able to move several hundred meters in a few hours.

Scientist 3

Water does collect in the playa, producing mud and ice. However, neither mud nor ice is responsible for the rocks’ movements. The playa is located along a fault line between tectonic plates. Minor vertical shifts in the plates cause the rocks to move downhill, leaving trails. Due to the combination of tectonic plate movement and strong winds, the rocks are able to move only a few meters over several years.

According to Scientist 2, friction between the rocks and the clay is reduced by which of the following?

The quadratic function f and triangle MPQ are graphed in the standard (x,y) coordinate plane below. Points M(2a, 5b), N(4a, 9b), and P(6a, 5b) are on f. Point Q(4a, 0) is NOT on f.

In terms of a and b, what is the area, in square coordinate units, of triangle MPQ?

Many humans carry the gene Yq77. The Yq test determines, with 100% accuracy, whether a human carries Yq77. If a Yq test result is positive, the human carries the Yq77 gene. If a Yq test result is negative, the human does NOT carry Yq77. Sam designed a less expensive test for Yq77 called the Sam77 test. It produces some incorrect results. To determine the accuracy of the Sam77 test, both tests were administered to 1,000 volunteers. The results from this administration are summarized in the table below.

It cost $2,500 to administer each Yq test and $50 to administer each Sam77 test. What was the total cost to administer both tests to all the volunteers?

The vector i represents 1 mile per hour east, and the vector j represents 1 mile per hour north. Maria is jogging south at 12 miles per hour. One of the following vectors represents Maria’s velocity, in miles per hour. Which one?

One side of square ABCD has a length of 12 meters. A certain rectangle whose area is equal to the area of ABCD has a width of 8 meters. What is the length, in meters, of the rectangle?

Given y = x/(x-1) and x > 1, which of the following is a possible value of y?

Loto begins at his back door and walks 8 yards east, 6 yards north, 12 yards east, and 5 yards north to the barn door. About how many yards less would he walk if he could walk directly from the back door to the barn door?

A cosine function is shown in the standard (x,y) coordinate plane below.

One of the following equations represents this function. Which one?

A bag contains 8 red marbles, 9 yellow marbles, and 7 green marbles. How many additional red marbles must be added to the 24 marbles already in the bag so that the probability of randomly drawing a red marble is 3/5?

Bar Codes: A Linear History

In 1948, graduate students, Norman Woodland and Bernard Silver, (1) took on a problem that had troubled retailers for years: how to keep track of store inventories. Inspired by the dots and dashes of Morse code, however, (2) Woodland and Silver created a system of lines that could encode data. Called a symbology, the pattern created by the spacing and widths of the lines encodes information by representing different characters.

The first bar code was composed of four white lines set at specific distances from each (3) other on a black background. The first line was always present. (4) Depending on the presence or absence of the remaining three lines, up to seven different arrangements were susceptible and, therefore, seven different encodings. Today, twenty-nine white lines making more than half a billion encodings possible.

To create a bar code scanner, Woodland and Silver adapted technology from an optical movie sound system. Their prototype scanner used a 500-watt bulb, a photomultiplier tube (a device that detects light), and an oscilloscope (a device that translates electronic signals into readable information). Although successful, the concoction was both large and costly. For example, progress stalled until the 1970s, when laser technology (both more compact and less expensive) became available.

In today’s scanners, a laser sends light back and forth across a bar code. While the black lines absorb the light, the white lines reflect it back at a fixed mirror inside the scanner. In this way, the scanner reads the symbology and decodes the information.

(5) Today, being that there are (6) one- and two-dimensional bar codes using numeric and alphanumeric symbologies. Bar codes are used not only for a pack of gum or an airline ticket, but also for research. In one study, for instance, tiny bar codes were placed on bees tracking (7) their activities. Shaping the way we gather, track, and share information, we have almost certainly exceeded even Woodland and Silver’s expectations.

For the part marked (1):

Bar Codes: A Linear History

In 1948, graduate students, Norman Woodland and Bernard Silver, (1) took on a problem that had troubled retailers for years: how to keep track of store inventories. Inspired by the dots and dashes of Morse code, however, (2) Woodland and Silver created a system of lines that could encode data. Called a symbology, the pattern created by the spacing and widths of the lines encodes information by representing different characters.

The first bar code was composed of four white lines set at specific distances from each (3) other on a black background. The first line was always present. (4) Depending on the presence or absence of the remaining three lines, up to seven different arrangements were susceptible and, therefore, seven different encodings. Today, twenty-nine white lines making more than half a billion encodings possible.

To create a bar code scanner, Woodland and Silver adapted technology from an optical movie sound system. Their prototype scanner used a 500-watt bulb, a photomultiplier tube (a device that detects light), and an oscilloscope (a device that translates electronic signals into readable information). Although successful, the concoction was both large and costly. For example, progress stalled until the 1970s, when laser technology (both more compact and less expensive) became available.

In today’s scanners, a laser sends light back and forth across a bar code. While the black lines absorb the light, the white lines reflect it back at a fixed mirror inside the scanner. In this way, the scanner reads the symbology and decodes the information.

(5) Today, being that there are (6) one- and two-dimensional bar codes using numeric and alphanumeric symbologies. Bar codes are used not only for a pack of gum or an airline ticket, but also for research. In one study, for instance, tiny bar codes were placed on bees tracking (7) their activities. Shaping the way we gather, track, and share information, we have almost certainly exceeded even Woodland and Silver’s expectations.

For the part marked (2):

Bar Codes: A Linear History

In 1948, graduate students, Norman Woodland and Bernard Silver, (1) took on a problem that had troubled retailers for years: how to keep track of store inventories. Inspired by the dots and dashes of Morse code, however, (2) Woodland and Silver created a system of lines that could encode data. Called a symbology, the pattern created by the spacing and widths of the lines encodes information by representing different characters.

The first bar code was composed of four white lines set at specific distances from each (3) other on a black background. The first line was always present. (4) Depending on the presence or absence of the remaining three lines, up to seven different arrangements were susceptible and, therefore, seven different encodings. Today, twenty-nine white lines making more than half a billion encodings possible.

To create a bar code scanner, Woodland and Silver adapted technology from an optical movie sound system. Their prototype scanner used a 500-watt bulb, a photomultiplier tube (a device that detects light), and an oscilloscope (a device that translates electronic signals into readable information). Although successful, the concoction was both large and costly. For example, progress stalled until the 1970s, when laser technology (both more compact and less expensive) became available.

In today’s scanners, a laser sends light back and forth across a bar code. While the black lines absorb the light, the white lines reflect it back at a fixed mirror inside the scanner. In this way, the scanner reads the symbology and decodes the information.

(5) Today, being that there are (6) one- and two-dimensional bar codes using numeric and alphanumeric symbologies. Bar codes are used not only for a pack of gum or an airline ticket, but also for research. In one study, for instance, tiny bar codes were placed on bees tracking (7) their activities. Shaping the way we gather, track, and share information, we have almost certainly exceeded even Woodland and Silver’s expectations.

For the part marked (3):

Bar Codes: A Linear History

In 1948, graduate students, Norman Woodland and Bernard Silver, (1) took on a problem that had troubled retailers for years: how to keep track of store inventories. Inspired by the dots and dashes of Morse code, however, (2) Woodland and Silver created a system of lines that could encode data. Called a symbology, the pattern created by the spacing and widths of the lines encodes information by representing different characters.

The first bar code was composed of four white lines set at specific distances from each (3) other on a black background. The first line was always present. (4) Depending on the presence or absence of the remaining three lines, up to seven different arrangements were susceptible and, therefore, seven different encodings. Today, twenty-nine white lines making more than half a billion encodings possible.

To create a bar code scanner, Woodland and Silver adapted technology from an optical movie sound system. Their prototype scanner used a 500-watt bulb, a photomultiplier tube (a device that detects light), and an oscilloscope (a device that translates electronic signals into readable information). Although successful, the concoction was both large and costly. For example, progress stalled until the 1970s, when laser technology (both more compact and less expensive) became available.

In today’s scanners, a laser sends light back and forth across a bar code. While the black lines absorb the light, the white lines reflect it back at a fixed mirror inside the scanner. In this way, the scanner reads the symbology and decodes the information.

(5) Today, being that there are (6) one- and two-dimensional bar codes using numeric and alphanumeric symbologies. Bar codes are used not only for a pack of gum or an airline ticket, but also for research. In one study, for instance, tiny bar codes were placed on bees tracking (7) their activities. Shaping the way we gather, track, and share information, we have almost certainly exceeded even Woodland and Silver’s expectations.

For the part marked (4): The writer is considering deleting the preceding sentence. Should the sentence be kept or deleted?

Bar Codes: A Linear History

In 1948, graduate students, Norman Woodland and Bernard Silver, (1) took on a problem that had troubled retailers for years: how to keep track of store inventories. Inspired by the dots and dashes of Morse code, however, (2) Woodland and Silver created a system of lines that could encode data. Called a symbology, the pattern created by the spacing and widths of the lines encodes information by representing different characters.

The first bar code was composed of four white lines set at specific distances from each (3) other on a black background. The first line was always present. (4) Depending on the presence or absence of the remaining three lines, up to seven different arrangements were susceptible and, therefore, seven different encodings. Today, twenty-nine white lines making more than half a billion encodings possible.

To create a bar code scanner, Woodland and Silver adapted technology from an optical movie sound system. Their prototype scanner used a 500-watt bulb, a photomultiplier tube (a device that detects light), and an oscilloscope (a device that translates electronic signals into readable information). Although successful, the concoction was both large and costly. For example, progress stalled until the 1970s, when laser technology (both more compact and less expensive) became available.

In today’s scanners, a laser sends light back and forth across a bar code. While the black lines absorb the light, the white lines reflect it back at a fixed mirror inside the scanner. In this way, the scanner reads the symbology and decodes the information.

(5) Today, being that there are (6) one- and two-dimensional bar codes using numeric and alphanumeric symbologies. Bar codes are used not only for a pack of gum or an airline ticket, but also for research. In one study, for instance, tiny bar codes were placed on bees tracking (7) their activities. Shaping the way we gather, track, and share information, we have almost certainly exceeded even Woodland and Silver’s expectations.

For the part marked (5): Which of the following true statements, if added here, would most effectively lead into the new subject of the paragraph?

Bar Codes: A Linear History

In 1948, graduate students, Norman Woodland and Bernard Silver, (1) took on a problem that had troubled retailers for years: how to keep track of store inventories. Inspired by the dots and dashes of Morse code, however, (2) Woodland and Silver created a system of lines that could encode data. Called a symbology, the pattern created by the spacing and widths of the lines encodes information by representing different characters.

The first bar code was composed of four white lines set at specific distances from each (3) other on a black background. The first line was always present. (4) Depending on the presence or absence of the remaining three lines, up to seven different arrangements were susceptible and, therefore, seven different encodings. Today, twenty-nine white lines making more than half a billion encodings possible.

To create a bar code scanner, Woodland and Silver adapted technology from an optical movie sound system. Their prototype scanner used a 500-watt bulb, a photomultiplier tube (a device that detects light), and an oscilloscope (a device that translates electronic signals into readable information). Although successful, the concoction was both large and costly. For example, progress stalled until the 1970s, when laser technology (both more compact and less expensive) became available.

In today’s scanners, a laser sends light back and forth across a bar code. While the black lines absorb the light, the white lines reflect it back at a fixed mirror inside the scanner. In this way, the scanner reads the symbology and decodes the information.

(5) Today, being that there are (6) one- and two-dimensional bar codes using numeric and alphanumeric symbologies. Bar codes are used not only for a pack of gum or an airline ticket, but also for research. In one study, for instance, tiny bar codes were placed on bees tracking (7) their activities. Shaping the way we gather, track, and share information, we have almost certainly exceeded even Woodland and Silver’s expectations.

For the part marked (6) :

Bar Codes: A Linear History

In 1948, graduate students, Norman Woodland and Bernard Silver, (1) took on a problem that had troubled retailers for years: how to keep track of store inventories. Inspired by the dots and dashes of Morse code, however, (2) Woodland and Silver created a system of lines that could encode data. Called a symbology, the pattern created by the spacing and widths of the lines encodes information by representing different characters.

The first bar code was composed of four white lines set at specific distances from each (3) other on a black background. The first line was always present. (4) Depending on the presence or absence of the remaining three lines, up to seven different arrangements were susceptible and, therefore, seven different encodings. Today, twenty-nine white lines making more than half a billion encodings possible.

To create a bar code scanner, Woodland and Silver adapted technology from an optical movie sound system. Their prototype scanner used a 500-watt bulb, a photomultiplier tube (a device that detects light), and an oscilloscope (a device that translates electronic signals into readable information). Although successful, the concoction was both large and costly. For example, progress stalled until the 1970s, when laser technology (both more compact and less expensive) became available.

In today’s scanners, a laser sends light back and forth across a bar code. While the black lines absorb the light, the white lines reflect it back at a fixed mirror inside the scanner. In this way, the scanner reads the symbology and decodes the information.

(5) Today, being that there are (6) one- and two-dimensional bar codes using numeric and alphanumeric symbologies. Bar codes are used not only for a pack of gum or an airline ticket, but also for research. In one study, for instance, tiny bar codes were placed on bees tracking (7) their activities. Shaping the way we gather, track, and share information, we have almost certainly exceeded even Woodland and Silver’s expectations.

For the part marked (7):

Bar Codes: A Linear History

In 1948, graduate students, Norman Woodland and Bernard Silver, (1) took on a problem that had troubled retailers for years: how to keep track of store inventories. Inspired by the dots and dashes of Morse code, however, (2) Woodland and Silver created a system of lines that could encode data. Called a symbology, the pattern created by the spacing and widths of the lines encodes information by representing different characters.

The first bar code was composed of four white lines set at specific distances from each (3) other on a black background. The first line was always present. (4) Depending on the presence or absence of the remaining three lines, up to seven different arrangements were susceptible and, therefore, seven different encodings. Today, twenty-nine white lines making more than half a billion encodings possible.

To create a bar code scanner, Woodland and Silver adapted technology from an optical movie sound system. Their prototype scanner used a 500-watt bulb, a photomultiplier tube (a device that detects light), and an oscilloscope (a device that translates electronic signals into readable information). Although successful, the concoction was both large and costly. For example, progress stalled until the 1970s, when laser technology (both more compact and less expensive) became available.

In today’s scanners, a laser sends light back and forth across a bar code. While the black lines absorb the light, the white lines reflect it back at a fixed mirror inside the scanner. In this way, the scanner reads the symbology and decodes the information.

(5) Today, being that there are (6) one- and two-dimensional bar codes using numeric and alphanumeric symbologies. Bar codes are used not only for a pack of gum or an airline ticket, but also for research. In one study, for instance, tiny bar codes were placed on bees tracking (7) their activities. Shaping the way we gather, track, and share information, we have almost certainly exceeded even Woodland and Silver’s expectations.

Consider the passage as a whole: Suppose the writer’s primary purpose had been to describe how a specific technological advancement changed business practices. Would this essay accomplish that purpose?