Is this correct? Why/why not?

Which feature do highland climates have that lower elevation areas do not?

Can someone me with questions 15 to 17 plz.

Which formula can be used to calculate the molar mass of ammonia (nh3)? molar mass of n + molar mass of h 3 × molar mass of n + molar mass of h molar mass of n + 3 × molar mass of h 3 × molar mass of n + 3 × molar mass of h