What is the most important reason to control the conditions of a experiment ?

Which of the following occurs most often in a population when genetic variation and overproduction are present? some organisms have a lower reproductive success than others. some organisms have a higher reproductive success than others. some organisms have no reproductive success. some organisms do not have genetic variation.

What are the most explosive events that occur on the sun? umbras solar flares solar winds prominences

Which feature would you expect to find in a population in which sexual selection depends on male competition?