Answer:
The heart valves
Explanation:
The heart valves prevent blood from flowing in the wrong direction in the heart. The valves are held in the proper place because of the chordae tendinae.
92 would be your answer have a very nice day
It is intended to increase immunity against that antigen back to protective levels, after memory against that antigen has declined through time.
Explanation:
Social behavior refers to the interactions that occur between two or more members of different species.
I am not sure but does it not already do that. Because i think it goes both ways so we can get sun <span />