Answer:
compound i guessed
Explanation: Compounds are two or more elements chemically combined in definite proportions by weight. Mixtures are two or more substances not chemically combined.
helium
has the most neutrons in the nucleus
pH = - log [H⁺]
pH = 7.5
pH + pOH = 14
7.5 + pOH = 14
pOH = 6.5
mass gives the mass of atoms while molecular weight gives the mass of molecules
Answer: the process by which cells use oxygen to break down sugar and obtain energy.