Why are photosynthesis and respiration so important to plants and animals?
Because it has a huge impact in ecosystem.
Photosynthesis is a proces in which sugar and oxygen are formed out of water and carbon dioxide. This means that the molecular carbon dioxide that we exhale is being absorbed by plants and converted into something useful. In addition to that, it is known that carbon emission, and generally carbon dioxide contribute to the global warming. Logically, it can be concluded that the plants are factors in minimizing that problem.
Respiration is the proces that occurs in plants as well as humans. In that proces, plants produce energy in the form of adenosine triphosphate (ATP), carbon dioxide, and water. This is pretty much that is happening in the human cell too. This is used for the development (growth) of a cell. Without developing or growing the photosynthesis rate would stay the same. However, when a plant grows, the cells divides, which results in the greater number of cells that are capable of photosynthesis than it was before division.