Answer:
Correct/valid answer is the lenght of daylight.
Explanation:
Abiotic basically means not living.
So, Populations of rabbits are living. It's defintely not that one.
Herbivores are living. So it's not that one.
Bacteria are living. So it's not that one.
Daylight is non living. So there's your answer.
Please mark as brainliest, I need just a few more :D