Question

How do coral animals obtain their food?
(a) They have tentacles that trap food particles.
(b) They are photosynthetic.
(c) They absorb predigested food through their cell wall from dinoflagellates which are photosynthetic.
(d) Both (a) and (c).

Answer 1

Hint: Coral come under phylum cnidaria, they are immobile and can’t make their own food. They form a symbiotic relationship between plant and animal but coral is animals because they are not able to make their own food.

Complete answer:
The scientific name of corals is Anthozoa and it belongs to phylum cnidaria in the Animal kingdom. Corals are tiny creatures found inside the ocean, coral is immobile and sessile. Corals are heterotrophs and carnivorous animals mainly corals depend on algae for food through photosynthesis. On the surface of coral algae gets attached and by sunlight algae make food which gives energy to corals. At night coral use their poisonous tentacles to trap zooplankton and tiny fishes. Dinoflagellates are zooxanthellae that occur in corals and the number of invertebrates, these Dinoflagellates helps to make food for the host through photosynthesis.

Additional Information: Coral reef- Coral is a polyp form of cnidaria and form colonies with other corals, coral attach to the surface of the ocean with the help of limestone present at the base, these limestone form coral reefs. The skeleton present in corals form pure gems. When coral dies, a cluster of limestone form. The largest coral reef is the Great Barrier reef which is found on the north-east coast of Australia is over 2,000 km long and found 90 miles away from shore. Coral are of a variety of shape and colour and form which make it attractive. Corals are also hiding places for the marine creature, when an aquatic animal of oceans feel danger they hide in between corals, but with increasing pollution and global warming, coral reefs are depleting.

So, the correct answer is both (a) and (c).

Note: Cnidarians are of two types polyp and medusae. Both of them are opposite in structure. In reproduction polyp from medusae by asexual reproduction and medusae form polyp by sexual reproduction, this is called Alternation of generation. Obelia and hydra are a common example of Alternation of generation.