Given a scientific passage and an answer, generate a question for the given answer.

Passage: Electrons are always added to the lowest energy level first until it has the maximum number of electrons possible, and then electrons are added to the next higher energy level until that level is full, and so on. The maximum number of electrons at a given energy level depends on its number of orbitals. There are at most two electrons per orbital. Answer: the lowest
Electrons are always added to which energy level first?

Passage: Solutes change the physical properties of solvents. They lower the freezing point and raise the boiling point of solvents. Answer: solutes
What change the physical properties of solvents?

Passage: Mammals breathe with the help of a diaphragm. This is the large muscle that extends across the bottom of the chest below the lungs. When the diaphragm contracts, it increases the volume of the chest. This decreases pressure on the lungs and allows air to flow in. When the diaphragm relaxes, it decreases the volume of the chest. This increases pressure on the lungs and forces air out. Answer: diaphragm
What muscle in the chest helps inflate and deflate the lungs?