learned behavior migration instinct response to stimuli reproductive strategy
I gave my students this multiple choice question: When the soil is saturated, earthworms move to the top of the soil to obtain oxygen. This behavior is evidence of which biological concept in earthworms?

Only one answer is correct among these 4 choices:
- learned behavior
- migration instinct
- response to stimuli
- reproductive strategy

Could you tell me which one is correct?

response to stimuli