Answer: When the oxygen-rich blood gets to the cells, the cells receive the oxygen and release the carbon dioxide. The blood with less oxygen and a lot of carbon dioxide returns to the heart. Then the heart returns this blood to the lungs where carbon dioxide is released and oxygen is received.
Explanation:
Answer:
Commensalism only occur among biotic factors
Explanation:
Abiotic factors are non-living factors that interacts with the biotic factor within an ecosystem. Commensalism is an association between two organisms in which one benefits and the other derives neither benefit nor harm.
From the above definition of commensalism, it is clear to note that it only involves two organisms rather than non-living organisms, hence; commensalism involves only biotic factors
The answer would be ''Y-Chromosomes Analysis''
I would say C.
I hope this helps.