Which of the following is not a way that machines provide a mechanical advantage?

a. change direction
b. change distance
c. change power
d. chance force

B. Change distance.
Distance is fixed and cannot be changed. The distance from A to B depends on the route you decide to take. There is no machine that can change "distance".

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.