Yes, both plants and animals need oxygen for cellular respiration. No matter which type of organism is doing cellular respiration, the inputs are glucose and oxygen and the products are carbon dioxide and water.

As you know, we can’t do photosynthesis, but plants can do both photosynthesis and cellular respiration. In photosynthesis, the inputs are carbon dioxide and water, with light as the energy source. The products are glucose and oxygen.

Think about a plant, such as a tree or a flower. Which parts of the plant are going to be able to do photosynthesis (hint: light)? All of the rest of the cells need to get their energy from the sugar made by the cells that can do photosynthesis. If a plant loses its leaves in fall, it has to live off of stored sugar until the following spring. That means using cellular respiration.