water changes from a liquid to a solid when you drop it below 32 F or 0 C. It also evaporates, changing into a gas in warmer weather.
water
Both temperature and pressure increase with depth.
At the center, both the temperature and the pressure are highest. Both a high pressure and a high temperature increase the likelihood of fusion.
Not enough pressure or temperature.
air pressure
yes
Booty
Pressure and temperature increase with depth beneath the surface of the Earth.
The boiling temperature of a liquid increases as the gas pressure a the liquid's surface increases.
Temperature is the average amount of energy that a (air) particle has. Pressure is the force that the moving particle exerts as it bumps into or pushes against a surface. The higher the temperature, the faster the particles will be moving and the more force they will exert when they bump into a surface. So as temperature goes up, so does pressure.
Boiling point
Any liquid tend to be evaporated; temperature and pressure have an important role.