It is supposed to flow through so heterotrophs(like humans etc) can gain energy from plants(autotrophs) which other animals gain energy from them eating each other which follows the food chain. Which keeps the food chain and life in order, by giving energy for work and life to sustain.
Enzymes are biological molecules (typically proteins) that significantly speed up the rate of virtually all of the chemical reactions that take place within cells. They are vital for life and serve a wide range of important functions in the body, such as aiding in digestion and metabolism.
It changes because it goes through phases of growth and changes size and it developed more.
Hope this helps.
