You are presented with the quiz "What can be reduced when a population suddenly gets much smaller?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "bottleneck effect occurs when a population suddenly gets much smaller" and "genetic variation can be reduced by random genetic drift, population bottlenecks, founder effect". 

So, what's the best answer to the question?


 

      Genetic variation     