[QA] Elephants _______ the ecosystems they live in, and make it possible for a lot of other species to survive in those environments as well.

Question:

Elephants _______ the ecosystems they live in, and make it possible for a lot of other species to survive in those environments as well.

• A.
  obtain
• B.
  remain
• C.
  maintain
• D.
  attain