The answer should be C. <span>Im not 100% sure though. the geosphere makes up the earth and its atmosphere as the lithosphere and its hydrosphere. </span>
The cycle runs like this:
Deoxygenated blood enters from the body to the heart via the superior/inferior vena cava. It goes directly to the right atrium and down to the right ventricle. From there it'll pass through the pulmonary artery into the lungs where diffusion will happen in the capillaries. Gas exchanges will occur and the blood will become oxygenated and return to the heart via the pulmonary vein. From the pulmonary vein it will enter back into the left atrium and then will give the final pump of oxygen rich blood into the aorta and then into the entire body.
Answer: molecule, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere
Explanation:
<span>Some of the first animals to develop an endoskeleton were: echinoderms.</span>
