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

You call materials able to conduct electricity with 100% efficiency, meaning that no energy is lost during the electrical transmission, superconductors.
What do you call materials able to conduct electricity with 100% efficiency, meaning that no energy is lost during the electrical transmission?

One of the properties of an air mass is that an air mass has similar temperature and moisture properties throughout it.
Which of the following is true regarding the properties of an air mass?

Gravity causes rocks to roll downhill.
Which force causes rocks to roll downhill?