Plant and animals depend on each …

Plants provide food and shelter for animals, and as they photosynthesize, regulate the levels of oxygen and carbon dioxide in the atmosphere.

As food producers, plants are eaten by herbivores, which in turn become food for the omnivores and carnivores. Plants are also the homes of many animals, small and big. Plants provide shelter from predators and harsh factors of the environment, like the hot sun, cold snow and torrential rain. When plants photosynthesize, they take in carbon dioxide and give out the fresh oxygen that all the animals need for respiration. Plants are crucial for the health of all animals.
Also, when animals die, they decompose and become natural fertilizers for plants. Being pretty much immobile, plants also depend on animals to pollinate them for reproduction. And when the fertilized plants eventually produce seeds encased in fruits, animals eat them or carry them along on their fur, dispersing the seeds far and wide, ensuring the continuity of the plant species.
On the other hand, plants depend on animals for nutrients, pollination and seed dispersal, and as the animals consume plants, they regulate the numbers of different species of plants. While plants provide oxygen for the animals as they photosynthesize, animals respire and give out carbon dioxide for plants to make food with. It is an interdependent relationship here. This is not to say that plants do not respire themselves. They do, it is just that the amount of carbon dioxide they give out is not enough for the plants to make enough food with. As such, plants need animals.