instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
A desmosome is a cell structure that anchors the ends of cardiac muscle fibers together.
answer:
A desmosome is a cell structure that anchors the ends of what fibers together?

question:
Competive exclusion princple explains why two different species cannot occupy the same niche in the same place for very long.
answer:
What explains why two different species cannot occupy the same niche in the same place for very long?

question:
Four many variables are used to describe the condition of a gas.
answer:
How many variables are used to describe the condition of a gas?