Câu hỏi:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

          Most people think that lions only come from Africa. This is understandable because in fact most lions do come from there but this has not always been the case. If we went back ten thousand years. we would find that there were lions roaming vast sections of the globe. However no, unfortunately only a very small section of the lion’s former habitat remains.

          Asiatic lions are sub-species of African lions. It is almost a hundred thousand years since the Asiatic lions split off and developed as a sub-species. At one time the Asiatic lion was living as  far west as Greece and they were found from there, but in a band that spreads east through various countries of the Middle East, all the way to India. In museums now, you can see Greek coins that have clear images of the Asiatic lion on them. Most of them are dated at around 500 B.C. However, Europe saw its last Asiatic lions roaming free to thousand years ago. Over the next nineteen hundred years the numbers of Asiatic lions in the other areas declined steadily, but it was only in the nineteenth century that they disappeared from everywhere but in India.

          The Gir Wildlife Sanctuary in India was established especially to protect the Asiatic lion. There are now around three hundred Asiatic lions in India and almost all of them are in this sanctuary. However, despite living in a sanctuary, which makes them safe from hunters, they still face a number of problems that threaten their survival. One of these is the ever-present danger of disease. This is what killed more than a third of Africa’s Serengeti lions in 1994, and people are fearful  that something similar could happen in the Gir Sanctuary and kill off many of the Asiatic lions there.

          India’s lions are particular vulnerable because they have a limited gene pool. The reason for this is interesting – it is because all of them are descended from a few dozen lions that were saved by a prince who took a particular interest in them. He was very healthy, and he managed to protect them otherwise they would probably have died out completely.

When you see the Asiatic lion in India, what you sense is enormous vitality. They are very impressive animals and you would never guess that they this vulnerability when you look at them.

The phrase “split off” in the second paragraph is closest in meaning to________.