THE AUTHOR REFERS TO THE OCEAN BOTTOM AS A "FRONTIER" IN LINE...

câu 36: - DE THI THU DAI HOC MON TIENG ANH VA DAP AN
Tiếng Anh DE THI THU DAI HOC MON TIENG ANH VA DAP AN
Câu 36: The author refers to the ocean bottom as a "frontier" in line 2 because it A.is not a popular area for scientific research B.contains a wide variety of life forms C.attracts courageous explorers D.is an unknown territory