That would be c, the alveoli.
The mass number of an atom is its total number of protons and neutrons. Atoms of different elements usually have different mass numbers , but they can be the same. For example, the mass number of argon atoms and calcium atoms can both be 40.
Answer:
MgF₂
Explanation:
Fluorine only has a 1- charge, so to satisfy the 2+ charge on magnesium–– you need 2 fluorine atoms to balance out the charges.
