Animal dander would be the answer you're looking for.
Hope this helps :)
Answer:
Veins
1l carry blood from tissue of the body to the heart
2) are usually found closer beneath the skin
3) are less muscular then arteries
4) collapse if blood flow stops
arteries
1) carry blood back away from the heart to the tissue of the body.
2) found deeper within the body
3) are more muscular then veins
4) would generally remain open even if blood stops because of it's muscular structure.
Answer: pretty sure it’s the number of mitochondria in muscle cells
Explanation:
