Aproposed ocean thermal-energy conversion (otec) system is a heat engine that would operate between warm water (23°c) at the ocean's surface and cooler water (7°c) 1,968 m below the surface. what is the maximum possible efficiency of the system? enter your answer accurate to two decimal places.

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

The best answer is (a) which is universal law is in effect at all times. it is constantly at play in everything we do and governs our lives. it is also important to note that universal law applies to not only everything on earth, but everything in the universe as well, which is another reason why it is in effect at all times.

  concave means having an outline or surface that curves inward like the interior of a circle or sphere. so the mirror curves inward.