Which of the following can impact the timing of the blowfly lifecycle?

The size of the person

The air temperature

The age of the person

The presence of leaves on the ground

Given that a blowfly starts its lifecycle only if there are appropriate conditions met, one of which is suitable temperature, the correct answers as to what can impact the timing of the blowfly lifecycle is the air temperature.

I don't see how humans will impact when this fly is going to be born, so A and C are incorrect. Leaves also doesn't really affect blowflies, which is why D is incorrect as well.