please help me this is due soon :(( giving brain liest for whoever does it right, and it does it in there own words, ITS OK IF A LITTLE IS FROM THE INTERNET :D pls help im giving brain liest :)

In many species, females choose the male they will mate with. For their part, males try to be chosen as mates. They show females that they would be a better mate than the other males. To be chosen as a mate, males may perform courtship behaviors. These are special behaviors that help attract a mate. Male courtship behaviors get the attention of females and show off a male’s traits. These behaviors are often observed as direct competition between males.  Different species have different courtship behaviors.

Explanation:

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation: