To determine the muzzle velocity of a bullet fired from a rifle, you shoot the 2.53-g bullet into a 2.49-kg wooden block. The block is suspended by wires from the ceiling and is initially at rest. After the bullet is embedded in the block, the block swings up to a maximum height of 0.203 cm above its initial position. What is the velocity of the bullet on leaving the gun's barrel

One splits the atoms and molecules  the other combines them

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.