Aboy on a bicycle is resting at the top of a hill. then, he rides his bicycle down the hill. describe how the boy's potential and kinetic energy differ at the top, middle, and bottom of the hill.

i have to report this, it doesn't relate to biology

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds