The ocean floor regions are the continental margins, the ocean basin floor, and the mid-ocean ridge.
It’s b, biocrusts help the environment
The answer is alveolates. The sac-like structures under their plasma membrane are called alveoli. The alveoli provide support to the plasma membrane. Examples of groups of alveolates are ciliates, such as Paramecium, dinoflagellates, apicomplexa, and foraminifera. They lie under the phylum, Ciliophora.
