Black holes are: a) star remnants from super massive stars which gravitational collapse can not be halt by electron or neutron degeneracy and gravity is so strong in their vicinity that not even light can escape. b) regions of the universe with space empty of matter or radiation that becomes so dark that forbids us from investigating it. c) regions of space where matters is not sufficiently hot to radiate in the visible spectrum.

Answer to the question provided is 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.

Is this a question of an answer