A) lipids because they are used to speed up chemical reactions
Answer:
5
Explanation:
Nitrogen has 5 electrons in its n=2 (outer) shell.
Flvs
The yolk sac functions to form blood cells in early development (embryonic phase) for nourishment of the embryo and early fetus. Towards the end of the 1st trimester, the yolk sac disappears and the placenta takes over for the fetus.
The arteries get "hard" and absorb less systolic force
