The force that pushes plates together is called: isostasy
Conservation is the one method of improving air quality among the following choices given in the question that does not require advanced technology. The correct option among all the options that are given in the question is the second option or option "b". This method only needs preserving the natural balance.<span />
A large area of flat land, that is at a high altitude is called a plateau. An excellent example of a plateau is Tibet.