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

A electron microscope is used to see extremely small objects.
What type of microscope is used to see extremely small objects?

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

During phase change, the temperature of a system remains constant.
What happens to the temperature of a system during phase change?