Question

Animals or organisms floating on the surface of water are known as
A. Plankton
B. Pelagic
C. Benthon
D. Neritic

Answer 1

Planktons are usually unicellular, microscopic organisms found in marine ecosystems. They are too small in size or non-motile or weak to swim against the current, and exist in a drifting state. The Plankton family provides a large web of food for freshwater or seawater creatures.

Complete answer:
Plankton is derived from Greek word planktos, which means drifter because plankton cannot move; they depend upon water current, tides and other factors for their movement. They are divided into two types.
1. Phytoplankton: A plant-like community is called phytoplankton.
2. Zooplankton: Animal like community is called zooplankton.
Zooplankton feed on phytoplankton and then these zooplankton eaten by the large marine fishes and some other species. Phytoplankton make their energy through photosynthesis. Plankton's population is needed for a thriving marine ecosystem, too many plankton in one area can create serious problems. When a plankton population suddenly swells, it’s called a “bloom.” When this happens with certain sorts of phytoplankton that release dangerous toxins, the region may experience a red tide or other serious algal bloom. These temporary conditions can cause high fish mortality and other damage to the marine ecosystem.
Pelagic is the zone of the water body. Benthos are the bottom dwellers that live in the bottom of the sea.

So the correct option is (A) plankton.

Note: Because the aquatic food chain depends so heavily on plankton, the survival of these tiny plants and animals is essential for healthy marine ecosystems. Climate change and rising sea temperatures pose serious risks to plankton populations. It is estimated that approximately 80% of oxygen is produced by phytoplankton.