Aclosed box has two metal terminals a and b. the inside of the box contains an unknown emf 8 in series with a resistance r. when a potential difference of 22.0 v is maintained between terminal a and terminal b, there is a current of 1.50 a between the terminals a and b. if this potential difference is reversed, a current of 1.90 a in the reverse direction is observed. find epsilon and r.

The correct answer is  "c".  it is "c" because melting is an endothermic change, and endothermic get's energy from surroundings. 

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.