Answer:
with each heartbeat,the heart pumps blood throughout our bodies,carrying oxygen to every cell,after delivering oxygen the blood returns to the heart the heart then sends the blood to the lungs to pick up more oxygen.
If later is was 100 million years ago, later b would be 200 million years ago (because it is 100millions years prior to a). And therefore layer c must b 300 million years ago.
Answer:
C directing the cell to create certain proteins.
Explanation:
They differentiate through the process of mitosis.
First one is C) A phosphate group is added, and the second is D) Kreb's cycle