Most nonmetals form covalent or ionic bonds, depending on the element with which they react. carbon predominantly forms covalent bonds since it has 4 valence electrons and can form single, double or triple bonds with other elements. what element will form an ionic bond with carbon?

From negative to negative

The answer is water molecules are split.cellular respiration and photosynthesis are complement  reactions to each other. these are reverse reactions. in cellular respiration glucose and oxygen yield water and carbon dioxide. so, when respiration begins,  glucose molecules are split. in the opposite reaction - in photosynthesis, carbon dioxide and water yield glucose and oxygen. thus,  when respiration begins, water molecules are split.

Answer mechanical energy;

Ibelieve the answer is arteries