Answer:
4
Explanation:
There are 4 nitrogenous bases and they are Adenine, Thymine, Cytosine and Guanine (in RNA, Thymine is replaced by Uracil)
I’m pretty sure it’s C but try googling it
A group of cells that performs a similar function is known as tissue.
Answer:
During exercise, your heart typically beats faster so that more blood gets out to your body. Your heart can also increase its stroke volume by pumping more forcefully or increasing the amount of blood that fills the left ventricle before it pumps.