What geological activities are often associated with convergent boundaries?

Convergent boundaries occur where two tectonic plates collide or move towards each other. This interaction leads to significant geological activities, most notably mountain building and subduction.

When an oceanic plate converges with a continental plate, the denser oceanic plate is forced under the lighter continental plate in a process called subduction. This subduction can create deep ocean trenches and lead to volcanic activity as the subducted plate melts and contributes to magma formation. Additionally, when two continental plates collide, neither plate is subducted due to their similar densities, which results in the crumpling and folding of the Earth's crust, leading to the formation of mountain ranges.

This geological activity is emblematic of the dynamic processes at convergent boundaries, making mountain building and subduction the correct answer in this context.