When does a cold front develop? a. when two masses of warm air meet b. when a cold air mass invades a warm air mass c. when two masses of cold air meet d. when a warm air mass invades a cold air mass

Which statements describe polyatomic ions? check all that apply. polyatomic ions have many charges. polyatomic ions have one overall charge. polyatomic ions repel other ions to form ionic bonds. polyatomic ions attract other ions to form ionic bonds. polyatomic ions are made up of only one type of atom. polyatomic ions are made up of two or more types of atoms.

What causes most sediment to wash or fall into a river

What does a numerical subscript following an element in a chemical formula mean?