What’s the authors purpose for writing the passage?
a. to condemn the illegal ivory trade
b. to describe the traits and behavior of elephants
c. to trace the reasons why elephants are endangered
d. to encourage readers to visit wildlife preserves.

C. To trace the reasons why elephants are endangered

Explanation:

I think this is the correct answer because the author doesn't only describe the illegal ivory trade as an important cause of the elephant's endangerment, it also focuses on the shrinking of their natural habitat.

The author starts describing some of the elephant's most interesting characteristics so the audience feels empathy towards them. Then he starts to mention the causes of their endangerment, first the poaching, and then the reduction of their habitats, making emphasis on the fact that both are very harmful.  

He finishes showing the effors to save this species.

As we can see, he doesn't focus on the behaviour of elephants so option B. is discarded.

Although the author condemns illegal ivory trade, he also focuses on other factors, so it is not option A.

And he mentions the wildlife preserves, he doesn't encourage the readers to go there, he only describe them as solutions.

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