Why is the heart such an important part of the circulatory system? Red blood cells are made in the heart
o If the heart did not remove water from the blood, blood pressure in the blood vessels would become dangerously high
O if the heart did not pump blood throughout the body, the blood could not deliver oxygen and nutrients or remove wastes
If the heart did not exchange oxygen for carbon dioxide, wastes would collect in the cells

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.