Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Thermosphere is the upper-most atmosphere.
What is the upper-most atmosphere known as?

Hemodialysis has a patient’s blood pass through a length of tubing that travels through an artificial kidney machine.
Which form of dialysis has a patient’s blood pass through a length of tubing that travels through an artificial kidney machine?

Topsoil layer of soil usually does not have very small particles like clay.

What layer of soil usually does not have very small particles like clay?