Question

Describe the distribution of active volcanoes, earthquake epicenters, and major mountain belts

Answer 1

Looking at the positions of most if not all volcanoes, earthquakes, and major mountain belts, they are distributed mainly around the tectonic plate boundaries.
This is because the boundaries push further away, move closer together, and slide against each other (convergent, divergent, transform), thus creating either mountains, volcanoes, or earthquakes. 

Answer 2

The distribution of the volcanoes, earthquake epicenters, and major mountain belts are distributed in close proximity of the borders of the tectonic plates.

Most of the active volcanoes nowadays are found at the so called ''Ring of Fire'' which is practically the border of the Pacific Tectonic Plate.

The earthquake epicentres are not found at only some specific place, but they are found everywhere where there's border between two or more tectonic plates, it doesn't matter do they collide, move away from each other, subduct, the earthquakes will be there.

The major mountain belts are found on places where tectonic plates of pretty much the same density collide, so instead of some of them to go and be subducted, they push against each other and lift the area up.