Q1:
What happens to the O2 and CO2 levels when one sprig of Elodea and one snail are put into a test tube with the lights on after 24 hours?
(A): Drastic changes with oxygen increasing and carbon dioxide decreasing.
(B): Drastic changes with carbon dioxide increasing and oxygen decreasing.
(C): Oxygen and carbon dioxide vary slightly, but stay around their original levels.
(D): There is no oxygen left in the test tube.
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Q2:
Which experiment yielded the most ideal conditions in the test tube for the snails and Elodea sprigs?
(A): 2 snails, 2 sprigs, lights on
(B): 1 snail, 2 sprigs, lights on
(C): 1 snail, 2 sprigs, lights off
(D): 1 snail, 2 sprigs, lights on
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Q3:
How do the snails and Elodea sprigs model interdependence?
(A): The snails receive oxygen and glucose from the Elodea sprigs. The Elodea sprigs receive oxygen from the snails.
(B): The Elodea sprigs receive oxygen and glucose from the snails. The snails receive oxygen from the Elodea sprigs.
(C): The snails receive oxygen and glucose from the Elodea sprigs. The Elodea sprigs receive oxygen, water, and light from the snails.
(D): The Elodea sprigs receive oxygen and glucose from the snails. The snails receive oxygen, water, and light from the Elodea sprigs.
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Q4:
You have an Elodea sprig in a test tube containing bromothymol blue. Then you watch it for several days. At what time of day will the oxygen level in the tube be the lowest?
(A): Just before sunset
(B): Midnight
(C): Just before sunrise
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Q5:
The two tubes contain bromothymol blue. The lights are on. After 24 hours, what will the color of the water be in tube D?
(A): Green (it won't change)
(B): Yellow
(C): Blue
(D): Colorless (clear)
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The diagram above is dedicated to the last question.
