Question

an estuary is
a a freshwater biome
b an area with a low concentration of minerals and nutrients
c characterized by deep water
d an ecotone
please select the best answer from the choices provided

Explanation:

An estuary is an ecotone, which is a transition area between two biomes (in this case, between freshwater and marine environments). It is rich in minerals and nutrients due to the mixing of fresh - water from rivers and salt - water from the ocean. It is not a freshwater biome as it has saltwater influence, not an area with low mineral/nutrient concentration, and not characterized by deep water.

Answer:

D. an ecotone