What makes up an isotope’s mass number? A.) The number of protons and neutrons
B.) The number of protons, neutrons, and electrons
C.) The number of stable isotopes of an element

because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). they locate the types of rock that are likely to contain natural gas deposits.