What molecule directly supplies the energy required for this transport?

explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.

a scenario where a cell may be needed to perform a form of endocytosis is when transporting large molecules. a scenario where a cell may be needed to perform a form of exocytosis is when releasing the large molecule from the cell.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.