Medium spiders will be the most plentiful. Large spiders will learn to hide from predators. Small and medium spiders will be the least plentiful. Small and large spiders will mutate.
I gave my students this multiple choice question: In a population of spiders there are three different sizes: small, medium, and large. The large spiders are easily seen by predators. Small spiders have a difficult time finding food. What will most likely happen to the population after many generations?

Only one answer is correct among these 4 choices:
- Medium spiders will be the most plentiful.
- Large spiders will learn to hide from predators.
- Small and medium spiders will be the least plentiful.
- Small and large spiders will mutate.

Could you tell me which one is correct?

Medium spiders will be the most plentiful.