For a printable
version of the Post-Test, click
What did you learn? Select
the best response to the questions below.
1. Fish remove dissolved
oxygen from water by using their .
2. Oxygen is dissolved
A. forming small bubbles.
B. bound to hydrogen to form water itself.
C. bound to carbon in the form of carbon dioxide.
D. as molecules associated with water molecules.
E. only in very warm areas.
3. The amount of dissolved
oxygen in water will increase by adding ____________.
4. The maximum percentage
of oxygen in water at 4ºC and 1 atom of pressure is ___________.
5. When do aquatic
plants contribute the most dissolved oxygen to water?
A. during the night
B. during the day
C. during periods when plants die
D. production of oxygen by plants is uniform
E. plants do not produce oxygen, they consume oxygen
6. If a pond has an unstable level of dissolved oxygen, the best
method of correction would be .
A. to add fertilizer
to the pond.
B. to add algae to the pond.
C. to add fish to the pond.
D. to pump air into the pond.
E. to expose the pond to direct sunlight.
7. One liter of water weighs .
A. one pound
B. one kilogram
C. one ounce
D. one milligram
E. one pint
8. You are standing
on the banks of a large lake where dozens of different kinds of
fish are floating dead on the surface. Which of the following things
is most likely to have occurred?
A. Bacteria in the water
infected the fish causing them to die.
B. Nitrates in the water poisoned the fish.
C. The dissolved oxygen levels dropped below 2 mg/L and the fish
D. The fish ate algae and died from toxins produced by the algae.
E. The temperature of the lake was too low for reproduction, so
the fish could not breed and died of advanced age.
9. When water is rapidly
moving, like in white water rapids, the turbulence the surface area
and the amount of oxygen dissolved in the water.
A. decreases; decreases
B. does not effect; increases
C. increases; increases
D. decreases; does not effect
E. decreases; increases
10. In general, which
of the following best describes the effects that dams have on dissolved
oxygen and water quality?
A. Dams increase dissolved
oxygen by slowing the flow of rivers and warming the water.
B. Dams have little or no impact on dissolved oxygen in water.
C. Dams decrease dissolved oxygen by decreasing aeration and slowing
D. Dams have devastating effects on the aquatic life behind the
E. Dams are beneficial to the aquatic life behind them.
11. Addition of fertilizer
to rivers and streams often results in:
A. an increase in the
amount of dissolved oxygen in the water.
B. an overgrowth of aquatic plants and algae.
C. an overgrowth of fish and other aquatic organisms.
D. a complete depletion of oxygen due to binding of oxygen by fertilizer.
E. an increase in mutations in fish.
12. You are serving
as a research scientist with the Environmental Protection Agency.
You are monitoring the health of rivers in an area by examining
the amount of oxygen dissolved in the water. In an effort to work
with the local industries, you ask companies along these rivers
to collect samples and determine the amount of oxygen dissolved
in the samples. You receive the following results.
Sewage Treatment Plant
River Golf Course
Dam and Electric Plant
You note one value
that causes you some alarm, and you immediately alert your boss
and tell her that you suspect one company is causing problems. Who
do you suspect and why?
A. Apple Sewage Treatment;
the levels of dissolved oxygen are too low considering the sewage
that is probably getting in the water.
B. Big River Golf Course; the levels of dissolved oxygen are too
high for the amount fertilizer that is probably entering the water.
C. Chattanooga Dam and Electric Plant; the levels of dissolved oxygen
are impossible to obtain under normal circumstances.
D. Durham Fertilizer Plant; the levels of dissolved oxygen are too
high for the amount of waste that is probably entering the water.
E. East River Sawmill; the levels of dissolved oxygen are impossible
to obtain under normal circumstances.