For a printable version of the Pre-Test, click here.

Select the best response to the questions below.

1. Which of the following is true concerning dissolved oxygen and fish?

A. Fish do not use oxygen so the amount of oxygen dissolved in water does not matter.
B. Fish remove oxygen from the atmosphere by coming to the surface and swallowing bubbles.
C. Fish remove oxygen from the water by using their gills.
D. The scales of fish have a vast blood supply and they remove oxygen dissolved in the water.
E. Fish can breathe with lungs when they need to.

2. The amount of oxygen dissolved in water is ______________the temperature of the water.

A. directly related to
B. inversely related to
C. exactly the same as
D. not influenced by
E. parallel to

3. What percentage of the atmosphere is oxygen?

A. 9%
B. 21%
C. 50%
D. 79%
E. 100%

4. When oxygen moves with respect to water, it mainly moves ______________________________________.

A. by diffusion from the air to the water, as air has a higher concentration of oxygen.
B. from the water to the air as large amounts of oxygen are produced by aquatic plants.
C. from air to water, as aquatic plants pull the oxygen from the air.
D. from the water to the air, as the temperature of water is more stable than the temperature of air.
E. from the water to the air, as water is more turbulent than the air.

5. You measure and determine the average amount of dissolved oxygen in five bodies of water over a year. Which one of the following would have the highest average dissolved oxygen?

A. a mountain lake with numerous, aquatic plants
B. a rapid flowing stream at the base of a mountain
C. a slow moving river in West Texas
D. a stagnant pond in East Texas
E. an underground river (aquifer)

6. You are investigating the die-off of numerous fish in a river that passes near a fertilizer plant. You are concerned that the plant may be dumping nitrates into the river. If you wanted to measure dissolved oxygen in the river when it was at its lowest, what time of day would be best to sample the water?

A. 5:00 a.m.
B. 10:00 a.m.
C. 2:00 p.m.
D. 5:00 p.m.
E. 10:00 p.m.

7. Which of the following does not increase the amount of dissolved oxygen in water?

A. diffusion from the atmosphere
B. bacteria in the water
C. plants in the water
D. rapid movement of water over rocks
E. algae in the water

8. The amount of oxygen dissolved in water is measured as________ and is the same thing as ________________.

A. mg/L; parts per billion
B. mg/L; parts per million
C. ounces/quart; parts per thousand
D. ounces/gallon; parts per million
E. mg/L; parts per thousand

9. As the altitude increases, assuming constant water temperature, the amount of oxygen dissolved in water ______________________.

A. stays the same
B. becomes unstable
C. increases, then stabilizes
D. increases
E. decreases

10. Dams can affect the amount of oxygen dissolved in water by all but which of the following ways?

A. slowing the flow of water
B. decreasing aeration of water
C. increasing the temperature of water
D. increasing the amount of bacteria in water

11. One problem that occurs when raw sewage enters rivers and streams is _____________________________________________.

A. the bacteria present consume large amounts of dissolved oxygen.
B. the bacteria present produce toxins that can kill fish.
C. the bacteria present produce toxins that can kill aquatic plants.
D. the sewage acts as fertilizer and causes plants to grow too fast.
E. chemicals used to treat raw sewage will kill both fish and aquatic plants.

12. You are serving as a research scientist with the Environmental Protection Agency. You are monitoring the dissolved oxygen of rivers in an area. You record the amount of oxygen dissolved in the Apple River near the Apple Sewage Treatment Plant to average 7 mg/dL. The amount of oxygen dissolved of the Big River near the Big River Golf Course averages 6.5 mg/dL. Additionally, measurements of dissolved oxygen from the Chattanooga River average 8.5 mg /dL near the Chattanooga Dam and Electric Plant. The Durham River has an average dissolved oxygen of 4 mg/dL near the Durham Fertilizer Plant, and the East River, near the East River Sawmill has an average dissolved oxygen of 8 mg/dL. Of the five riverside industries, which is most likely ignoring guidelines on maintaining water quality?

A. The Apple Sewage Treatment Plant
B. The Big River Golf Course
C. The Chattanooga Dam and Electric Plant
D. The Durham Fertilizer Plant
E. The East River Sawmill

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