Corals are
Corals are
- Poriferans attached to some solid support
- Cnidarians, that are solitary living
- Poriferans present at the sea bed
- Cnidarians that live in colonies
Answer
Corals are marine invertebrates of phylum-Cnidaria. They live in compact colonies of many identical individual ‘polyps’. The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.
Although some corals can catch small fish and plankton, using stinging cells on their tentacles, like those in sea anemone and jellyfish but most corals obtain the majority of their energy and nutrients from photosynthetic unicellular algae that live within their tissue.
The correct option is D.