Questions are in the image.pls briefly explain each for a, b,c, d and e

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.

the answer is d p: cell, q: organ, r: organ system, s: tissue

plato users:

d.  

there was a variety of food available on island x, but there were only large seeds and nuts on island y.