How does the air changes as you get higher up

The velocity of any object depends upon a) the location of the object. b) the location of the observer. c) which measurement tools are used. d) the relative motion of the observer.

Avogradoa number was calculated by determining the number of atoms in?

32p and 31p are two isotopes of phosphorus. compare the number if subatomic particles that are present in the atoms of these isotopes.