How does changing one variable in a controlled experement a scientist

What stress will shift the following equilibrium system to the left? n2(g) + 3h2(g) ⇌ 2nh3(g) adding more n2(g) adding more nh3(g) increasing the pressure of the system reducing the volume of the container

When balancing a chemical equation:

In what environment would mineral formation caused by high pressures and high temperatures most likely occur?