Answer:
The nektonic organisms are those marine organisms that are found in almost every depth. These can move freely from one place to another in the ocean body due to its ability to swim. For example, Turtles, sharks, Fishes, and dolphins.
The planktonic organisms are passive swimmers, as they can move along with the ocean currents and are mostly found in the upper portion of the ocean body. For example, Diatoms and Rotifers.
The benthos is the bottom-dwelling organisms that cannot swim. For example, Bivalves, Corals and Sponges.
The nektonic organisms are different from the planktons and the benthos because the nektons can easily swim. They are constructed with such body parts that allow them to swim and migrate from one region to another region within the ocean water body. Whereas the planktons and the benthos cannot migrate easily and are considered as sessile organisms.
