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

Breast cancer is the most common type of cancer in adult females.
What is the most common type of cancer in adult females?

A covalent network solid is a compound in which all of the atoms are connected to one another by covalent bonds.
What is a compound in which all of the atoms are connected to one another by covalent bonds?

High altitude above sea level causes the alpine tundra to be so cold.
What causes the alpine tundra to be so cold?