I am sooo confused, nun of the questions on my hw are on here therefore I have no Idea how to do them

This is the substance(s) formed in a chemical reaction.

What causes the development of most clouds and precipitation in the atmosphere?

Which statement best describes the superposition principle? a.) if two in-phase waves arrive simultaneously at a point, their amplitudes add up b.) if two out-of-phase waves arrive simultaneously at a point, their amplitudes add up c.) if two in-phase waves arrive at a point one after another, their amplitudes add up d.) if two out-of-phase waves arrive at a point one after another, their amplitudes adds up