How is the reading of a barometer affected when it is taken to (i) a mine, and (ii) a hill ?

What do the following indicate in a barometer regarding weather —

(a) gradual fall in the mercury level,

(b) sudden fall in the mercury level,

(c) gradual rise in the mercury level ?

We do not feel uneasy even under the enormous pressure of atmosphere above as well as around us. Give a reason.

Describe an experiment to demonstrate that air exerts pressure.