Which of the following is NOT a defining feature of mountains? Significant height above sea level
Prominence (the fact or condition of standing out from something by physically projecting or being particularly noticeable.)
Steepness
Cold weather

Consider an insulating crystal, made up of layers of atoms. what form would you expect the temperature dependence of the phonon heat capacity to approach at extremely low temperatures if the interlayer coupling is i)very strong (rigid coupling), and ii) very weak. explain.