Question

which event causes the formation of trenches in earths crust?
magma rising
mantle emerging
volcanoes erupting
lithosphere colliding

Explanation:

Trenches are formed at subduction zones where one tectonic plate (part of the lithosphere) collides with and is forced beneath another. Magma rising is related to volcanic activity at mid - ocean ridges. Mantle emerging is not a direct cause of trenches. Volcanoes erupting are a result of magma movement but not the cause of trench formation.

Answer:

lithosphere colliding