I think verterbrates have a back bone others do not. I only THINK so.
From lowest to highest hierarchy it would be: planet, star, solar system, galaxy.
B) cortisol ensures that the brain has glucose when it’s necessary. Cortisol is a steroid hormone that helps control blood sugar levels, metabolism, and inflammation. Glucose, also known as sugar, is an energy source used in cells in the body. The brain is highly demanding of energy since it is so rich in nerve cells and neurons, so glucose is essential to the brain. Too much can harm the brain though, so it is important for the cortisol to control the sugar levels.
Answer:
Symbiosis
both species benefit in this symbiotic relationship
