What do wind turbines, hydroelectric dams, and ethanol plants have in common?

a. all produce electrical current with pollution
b. all use generators to produce electrical current
c. all convert gravitational potential energy to electrical current
d. all convert thermal energy to electrical current

Option b is right that is  All use generators to produce electrical current

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.

45 is the correct answer