Can anybody help me with #3, #4, and #8 you can use the letters more than once

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.

All vaccination should(n’t) be mandatory! 1.at least 5 sentences explaining 2.why? 3.in the end summarize the sentence

Which of the following is a common response to cell signaling?