Please explain what a control group is, and what it does in a experiment.

a control group is a group who does NOT get the treatment. they are there so you can compare results with a group who hasn't had anything changed. this makes the results more valid & prevents bias. usually the control group THINKS they are getting the treatment but it's just a sugar pill or non-effective medicine

b is the best answer for this question.

answer; i believe the correct answer is (sporophyte);