Question

which adjustment knob(s) can you safely use when this objective is in place? only the coarse adjustment knob only the fine adjustment knob both the coarse adjustment knob and the fine adjustment knob

Explanation:

This question is about microscope usage (a common topic in Biology, part of Natural Science). When using high - power objectives (implied by "this objective" context), only the fine adjustment knob is used to avoid crashing the objective into the slide. So the correct option is the one stating only the fine adjustment knob.

Answer:

B. Only the fine adjustment knob