Circulatory -
Brings oxygen and nutrients where it is needed, removes toxic chemicals, maintains a stable body temperature
Digestive -
Food and nutrients are absorbed in the small intestine. These nutrients are necessary for other body systems to maintain homeostasis.
Excretory -
Removes all waste from the body, kidneys filter chemicals, liver filters toxins
Well, it's obvious, because without a transport system, cells wouldn't have the nutrients and things they needed!! And waste wouldn't be able to circulate out of cells.
According to Charles Darwin's theory of evolution by natural selection, organisms that possess heritable traits that enable them to better adapt to their environment compared with other members of their species will be more likely to survive, reproduce, and pass more of their genes on to the next generation. The next generation will have the things they will need to survive and the longer the generation goes the more fetchers they will have.
