1. excretory -Excretory systems regulate the chemical composition of body fluids by removing metabolic wastes and retaining the proper amounts of water, salts, and nutrients.
2. endocrine - The endocrine glands secrete hormones into the surrounding interstitial fluid; those hormones then diffuse into blood and are carried to various organs and tissues within the body.
3. reproductive - the system helps in giving birth to a new life
Explanaton:
did some research while taking the test on plato got a 20/20.
The endocrine system is a chemical messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In humans, the major endocrine glands are the thyroid gland and the adrenal glands.
Because at some point our organs get tired and weak from all the years of pumping and circulation etc. so at some point our bodies just can't do that forever...
