Question

Is coral biotic or abiotic

Answer 1

it's biotic, since it is a plant

Answer 2

it is both.

but mostly biotic.

when coral is forming, it is forming by creatures, not plant, these creatures are microscopic but coral is often mistaken as a plant because of how it obtains food. onces the organism dies, it solidifies into a petrified state, ((ROCK))

btw, did you know it coral is under any stress,they literally explode