All of the following are threats to biodiversity except
a. habitat destruction.
b. gene pool diversity.
c. pollution.
d. exotic species.

Biodiversity is the variety of living organisms on earth. Gene pool diversity is the variation of genes that exists within a species. Also, it prevents harmful diseases and helps species adjust to changes in the environment. The answer is letter B. the rest are threats to biodiversity. Exotic species are a threat to biodiversity because they alter the ecosystem of that area. They share food and habitat resulting in unbalanced ecosystem. Also, habitat destruction destroys the habitat of all the life forms in that area. 

it is false because i took the test and got it right hope it helps

Common noun. Although if it's like Aunt SoandSo then it's a pro-noun. But if it's just aunt, like, my aunt and I went shopping. Then it's a common noun.