NEED HELP ASAP, WILL GIVE BRAINLIEST Which phrase describes air pressure?

decreases with denser air
decreases as altitude decreases
equals mass divided by volume
decreases as a result of fewer air particles pushing down

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.

The answer is periosteum

Phagocytes contain digestive enzymes to facilitate the process of phagocytosis