Question

Which two categories of organic compounds store energy? (i know one is carbohydrates)

Answer 1

Any molecule containing lots of relatively stable, low energy bonds will be good at storing energy. Carbohydrates definitely fit that description. You should also think about lipids - they are basically built of hyrdrocarbon tails, with many singly (most often) bonded carbons and the other valence electrons on the carbons provided by hydrogen atoms...