The relation between the plants, animals and carbon can be described in the following way:
Plants uptake the carbon dioxide present in the environment by the process of photosynthesis that utilizes carbon dioxide to produce energy in the pressence of sunlight and chlorophyll.
During the process of photosynthesis oxygen is released into the environment to be used by the animals.
Homeostasis refers to the relatively stable state inside the body of an animal. Animal organs and organ systems constantly adjust to internal and external changes in order to maintain this steady state