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 #4 : Biochemical Cycles

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

Possible Answers:

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

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

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

Phosphorus is not fixed in the atmosphere by lightning.

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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