Answer:
Arteries carry oxygenated blood away from the heart. Veins carry the blood back to the heart. Veins contain valves that ensure blood flows in only one direction. Arteries don’t require valves because pressure from the heart is so strong that blood is only able to flow in one direction.
Explanation:
Answer:
the answer is increase the number of coils
Explanation:
They help convert nitrogen to nitrate which is usable by living beings. (Living beings can't use regular nitrogen)
Answer:
Neutrophils and Macrophages
Explanation:
