GRE Subject Test: Biology : Understanding Chemical Cycles

Study concepts, example questions & explanations for GRE Subject Test: Biology

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Example Questions

Example Question #1 : Biochemical Cycles

The phosphorus cycle is fundamentally different from the nitrogen and sulfur cycles. How so?

Possible Answers:

The phosphorus cycle does not include a gaseous phase, resulting in no significant quantities of atmospheric phosphorus.

Phosphorus does not enter the cycle from weathering of sediments and parent material.

Phosphorus is not fixed in the atmosphere by lightning.

Phosphorus is not taken up by plants and is a strictly inorganic cycle.

Phosphorus is cycled back into the soil through precipitation.

Correct answer:

The phosphorus cycle does not include a gaseous phase, resulting in no significant quantities of atmospheric phosphorus.

Explanation:

The phosphorus cycle does not contain an atmospheric phase, while both the sulfur and nitrogen cycles do.

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