Question

the bacterium mycobacterium smegmatis contains an enzyme capable of converting hydrogen from the atmosphere directly into energy. this rare ability allows m. smegmatis to survive in volcanic craters, the soil of antarctica, and other environments that are ______ most forms of life due to a lack of nutrients and light. which choice completes the text with the most logical and precise word or phrase? a hostile to b compatible with c constrained by d derived from

Explanation:

To solve this, we analyze the context: the environments (volcanic craters, Antarctica) lack nutrients and light, so they are harsh for most life. Let's evaluate each option:

• Option A: "hostile to" means the environment is harmful to most life, which fits (since M. smegmatis can survive, but others can't due to harshness).
• Option B: "compatible with" would mean the environment suits most life, but the text says "due to a lack of nutrients and light" (harsh), so B is wrong.
• Option C: "constrained by" implies the environment limits most life, but the focus is on the environment being harmful, not just limiting. "Hostile to" is a better fit for the harshness.
• Option D: "derived from" is about origin, which doesn't fit the context of the environment's effect on life.

So "hostile to" logically completes the sentence as the environments are harmful to most life.

Answer:

A. hostile to