The Next Few Questions Refer to the Following Description and Table

question 23

Multiple Choice

The next few questions refer to the following description and Table 28.1.
Diatoms are encased in Petri-platelike cases (valves) made of translucent hydrated silica whose thickness can be varied. The material used to store excess calories can also be varied. At certain times, diatoms store excess calories in the form of the liquid polysaccharide, laminarin, and at other times as oil. The following are data concerning the density (specific gravity) of various components of diatoms, and of their environment.
Table 28.1 Specific Gravities of Materials Relevant to Diatoms

-Using dead diatoms to "pump" CO₂ to the seafloor is feasible only if dead diatoms sink quickly. Consequently, application of mineral fertilizers, such as iron, should be most effective at times when diatom valves

• A) are thickest, and laminarin is being produced rather than oil.
• B) are thickest, and oil is being produced rather than laminarin.
• C) are thinnest, and laminarin is being produced rather than oil.
• D) are thinnest, and oil is being produced rather than laminarin.

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Definitions:

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Money owed to a company from a customer that is deemed unlikely to be paid, often resulting in a write-off.