D. rift valleys.
Trenches occur at convergent oceanic plates; fossils are extremely old bones, bodies, or footprints, which have gotten so old the intervening years have turned them into rock; U-shaped valleys are valleys which are shaped like the letter U, and are usually formed by glaciers, which tend not to occur underwater very often.
IFloration isn't even mentioned in the dictionary so I cannot help quite yet. Maybe the wrong word was used or something. IF not i will try my best to help anyway but please check so I can help to my fullest
Answer: The volcano popocatepetl is in Mexico.
A subduction zone is also generated when twooceanic plates collide — the older plate is forced under the younger one — and it leads to the formation of chains of volcanic islands known as island arcs.
