Final answer:
In animal cells, energy often comes prepackaged as carbohydrates, which are initially produced by plants through the process of photosynthesis.
Step-by-step explanation:
In animal cells, energy arrives prepackaged often in the form of carbohydrates. During the process of photosynthesis, plants convert light energy into chemical energy, which is then stored in carbohydrates such as glucose. Animals consume these carbohydrates and use the chemical energy stored within them to fuel their own cellular processes. The chemical reactions of photosynthesis provide the glucose that serves as this energy source, with the help of energy-carrying molecules like ATP and NADPH.