instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
Breast cancer is the most common type of cancer in adult females.
answer:
What is the most common type of cancer in adult females?


question:
Deep currents are caused by differences in density at the top and bottom of the ocean.
answer:
What is caused by differences in density at the top and bottom of the ocean?


question:
Simple kind of diffusion do small hydrophobic molecules squeeze through lipid molecules.
answer:

What kind of diffusion do small hydrophobic molecules squeeze through lipid molecules?