I believe it’s C because the heart pumps blood through the body
Help earth it helps u that’s what I believe
The answer to this question is summer I know this for a fact cause I took biology last year your welcome
Answer:
refers to the number of times the heart beats within a certain time period, usually a minute.
Or
it is the speed of the heart beat measured by the number of contractions of the heart
Answer:
Explanation:
i m not confirmed but i think hag fishes are present before vertebrates