Answer:
i think its A but dont take my word for it
Explanation:
Gases in Earth's Atmosphere. Nitrogen and Oxygen are by far the most common. Dry air is composed of about 78% Nitrogen (N2) and about 21% Oxygen (O2). Argon, Carbon Dioxide (CO2), and many other gases are also present in much lower amounts; each makes up less than 1% of the atmosphere's mixture of gases.
So therefore Oxygen is the gas that makes up the largest portion of the Earths Atmosphere.
Answer:
b. Capillaries; veins; arteries
Explanation:
Capillaries are the blood vessels with very thin walls. They serve as a site for an exchange of substances such as respiratory gases, nutrients, and toxins between the blood and the cells of the tissues. Veins are the blood vessels that mostly pick the deoxygenated blood from the body cells and deliver it to the heart for oxygenation. On the other hand, arteries are the blood vessels that mostly carry the oxygen-rich blood. They pick the oxygenated blood from the heart and deliver it to body cells. Therefore, veins carry blood towards the heart while arteries carry it away from the heart.
