The answer would be Uracil.
It is on the organ level. The heart consists of cardiac muscle tissue and is part of the cardiovascular organ system. It is basic for the human body to work properly since it provides oxygen for the human body.
Answer:
What sends oxygenated blood back to the heart from the lungs?
Oxygen-rich blood flows from the lungs back into the left atrium (LA), or the left upper chamber of the heart, through four pulmonary veins. Oxygen-rich blood then flows through the mitral valve (MV) into the left ventricle (LV), or the left lower chamber.
Explanation:
D. would be the most accurate because you can't make waste without developing also you get energy from developing so D would be the correct answer
Answer:
An invented long word said to mean a lung disease caused by inhaling very fine ash and sand dust.
Explanation: