A cannon fires a cannon ball at an enemy ship. The cannonball hits the ship at the same level as it was launched. Over its entire flight (after it leaves the cannon, before it hits the enemy ship), the work done by gravity and the work done by air resistance, respectively, are

The answer should be a.

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.