the pH of the water the clarity of the water the pressure of the water the temperature of the water
I gave my students this multiple choice question: A daphnia population shows a vertical migration from the bottom of a one-meter-deep pond during the day to the surface of the pond at night. To which factor is the daphnia population most likely responding?

Only one answer is correct among these 4 choices:
- the pH of the water
- the clarity of the water
- the pressure of the water
- the temperature of the water

Could you tell me which one is correct?

the temperature of the water