The most fundamental difference between plants and animals is that plants have cells which contain chloroplasts, whereas animals do not. Chloroplasts are tiny structures containing the green pigment chlorophyll. The sugar molecules produced in this photosynthesis are linked together in chains to make larger carbohydrate molecules, mainly starches and cellulose. The oxygen gas is released into the atmosphere. Animals cannot make their food in this way, but must depend upon plants or other animals for food.
Plants take the sun's energy and store it in high-energy food substances that animals can use.