The large diversity of biological molecules depends on atoms of the element .A. This element can make stable bonds to itself and to atoms of other elements. B. Without this element, the large macromolecules that make up most of the molecules in living organisms would not be possible.

carbon-With four electrons that can be shared to make covalent bonds, carbon-based molecules display an enormous variety of size, shape, and properties.

Explanation:

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.

brain development. a child's brain undergoes an amazing period of development from birth to three—producing more than a million neural connections each second. the development of the brain is influenced by many factors, including a child's relationships, experiences and environment.

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