Answer:
Answer is Sinoatrial node, SA.
Explanation:
The sinoatrial node, SA, is known to be a group of cells which are found at the top of the heart.
The electrical signal that is initiated by the sinoatrial node bring about or stimulates the atria and then the ventricle of the heart.
It should be noted that, the sinoatrial node are regarded as the pacemaker cells.
C.) viruses need a living host to reproduce... this is cause by viruses being Dioxyriboneuclicacid(DNA) surrounded by a protien shell so viruses are not alive per say.... but they get into cells and use living cells to reproduce
This is potential energy because while he was aiming at a bull's eye target, he is storing energy
Clues such as fossils such as bones, footprints, tar, etc, preserved underground helped inform scientists. You can also count how old a tree is when you cut it open and there are some alive for thousands of years so that is a possible way.
A) 100% EEFF
b) 50% Ef, 50% ef
c) 100% ef
d) 25% Fe, 25% EF, 25% Ef, 25% ef
