Which of the following is true of coral?
a. it is located in deep sea regions.
b. it supports few species.
c. it is a large and complex organism.
d. it is composed of thousands of individuals.

Coral can be found in deep waters but they grow in greatest abundance in sunny shallow warm waters near the coast. Corals support heaps of species. ie shelter for fish, food for crabs, etc. It depends on your version of 'large' most are relatively small-ish. complex = differs. 
So, Corals are composed of many small individuals that create hard structures to live in, which is what we know as coral. Unlike popular belief, coral are not plants and they are especially not rocks. They are animals, just that they are extremely small and shy. The animal is called a polyp and they live in large groups of millions. So yeah, the answer is D. I study marine biology and I am a scuba diver. Believe me I know what I am talking about.

No a triangle cannot be formed because when you add the two smallest number together (which would be 11) the have to be bigger than the number it is "against" ( which would be 12)