Both kelps and coral reefs are composed of algae that grow in the shallow parts of the ocean in warm and sunny waters. However, kelp forest grows in nutrient-rich waters while corals can develop in low nutrient waters.
Kelp forests are therefore common where warm and cold current meet in an up-welling. Coral reefs are borne of a symbiotic relationship between coral polyps and algae. The coral forms a rigid carbon skeleton of calcium carbonate while kelps are long flexible algae plants.
Plasma membrane is a part of the cell made of a lipid bilayer and an embedded protein layer. It protects the cell from the surroundings and also controls the materials leaving or entering the cell. The membrane is semipermeable and therefore allows certain materials to enter or leave the cell. In this case, the plasma membrane may prevent unlimited flow of water into or out of the cell.
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If they live in a river, they would most likely need fins (to swim) and gills (to breathe under water)
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