C. The problem of endangered species
Breaking chemical bonds is typically an endothermic process, which means energy must be added (it must pull in energy)
Breaking of chemical bonds is always endothermic meaning it wants energy, so it takes energy from its surroundings and sucks it in. Think of 'endo' as inside. The chemical bonds want energy inside of it so it can break.
Forming of chemical bonds is exothermic, meaning it releases energy into its surroundings. Think of 'exo' as outside, or exterior, it releases its energy outside of itself.
I hope that makes some kind of sense :)
PP and pp, there are homozygous because there are the same letter