Final answer:
Phototrophs get their energy from light, while chemotrophs get their energy from chemicals.
Step-by-step explanation:
Organisms can be identified by the energy source they use. There are two types of organisms based on their energy source: phototrophs and chemotrophs. Phototrophs get their energy from light, while chemotrophs get their energy from chemicals. Chemotrophs can be further divided into organotrophs, which obtain energy from organic compounds, and lithotrophs, which get energy from inorganic compounds.