20 which term is described as a long narrow depression in the ocean

(a) abyssal plains

(b) deep-sea trenches

(c) guyots

(d) continental shelf

The answer is B. deep-sea trenches. A trench is a type of excavation or depression in the ground that is generally deeper than it is wide (as opposed to a wider gully, or ditch), and narrow compared to its length (as opposed to a simple hole). In geology, trenches are created as a result of erosion by rivers or by geological movement of tectonic plates.

D, the answer is letter d. because even though fossil fuels take a very long time to form, they do form in the ground just like coal and others.

Answer they are produced by collision of tectonic plates;