Explain how ocean ridges and trenches are formed.

They are mid-ocean ridges, which form where two tectonic plates are spreading apart, which is called seafloor spreading. Tectonic plates are large pieces of the earth's crust, and they interact in a number of ways. Where they pull apart is called a divergent plate boundary.

When the tectonic plates in the Earth move away from each other they create trenches, ocean ridges are also formed by the Earths tectonic plates.

Answerwill have thinner; have thicker oceanic sediments;