The brown tree snake is used as an example of a(n)
a. poisonous species
b. endangered species
c. invasive species
d. domesticated species

c. invasive species

Invasive species can threaten an ecosystem and the biodiversity of the organism that exist in the present environment when the invasive species increase rapidly in number. 
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. 

Yes they are correct good day

He should put sand around the spill in order to contain it so that it won't spread