Why is a rainbow continuous?

How much energy is made when a pice of wood burns. how do you know

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons

The msds for glacial acetic acid says that it is a flammable liquid that can severely burn any human tissue it comes in contact with. it reacts with bases, various metals, and strong oxidizing agents. its vapors can form explosive mixtures with air.