How can you get energy as a living organism?

Organisms, such as humans, take in "substrates" such as glucose, in our food. During a process called respiration, we react these substrates with oxygen to give carbon dioxide and water; this takes place in the mitochondria of our cells.

Explanation:

For plants, they must make their own energy (food) through the process of photosynthesis, using sunlight, water and CO² to produce their food.

Animals and humans however cannot make their own food, and must consume food such as plants or other organisms to get energy.