instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
Processing of filtrate in the proximal tubule helps maintain the ph level in body fluid.
answer:
Processing of filtrate in the proximal tubule helps maintain what level in body fluid?

question:
A fewer predators is most likely to cause the number of rabbits living in an area to increase.
answer:
Which factor is most likely to cause the number of rabbits living in an area to increase?

question:
Because the solute is moving down the concentration gradient, and no input of energy is required, facilitated diffusion is considered a(n) passive type of transport.
answer:
Because the solute is moving down the concentration gradient, and no input of energy is required, facilitated diffusion is considered what type of transport?