Which of the following is an example of a biotic factor? the salinity level in a salt marsh the temperature of water at the seafloor the shrimp population in a bay the amount of sunlight reaching a seagrass bed

"The amount of sunlight reaching a seagrass bed"

the answer to your question is sperm

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.