Read the following passage and choose the best answer (A, B, C, D):
Alemur is a unique animal. When you look at a lemur, it might be hard to tell what you are really looking at. With their huge dark eyes and lush fur, lemurs are very cute, but what animal family are they from? Some lemurs look like a cross between a cat and a dog. Some look a little like squirrels, while others resemble monkeys. Why do they look so strange? To answer to this question we need to understand the lemur's history and genetics. In modern biology, lemurs are called prosimians. This means before monkeys. Remarkably, lemurs, monkeys, apes, and humans all share a common ancestor from about 50 million years ago. Monkeys, apes, and humans developed together in one direction. However, lemurs developed differently and slowly because of their geographical location. All lemurs come from the island of Madagascar, located off the east coast of Africa. Madagascar split off from mainland Africa 50 million years ago. It is believed that the first prosimians traveled to Madagascar on floating trees and plants. The prosimians that traveled to Madagascar were isolated from the rest of Africa. Predators, like dogs or cats, did not make it to Madagascar. Since there were no dangerous threats, prosimians did not have to evolve as quickly as other primates did. (primates: any nimal that belongs to the group of mammals that includes humans, apes, and monkeys.) Over time, the original prosimians evolved into lemurs. Lemurs have changed in some ways over those 50 million years, but they are much more similar to our shared ancestor than either humans, monkeys, or apes. Because of this, their bodies and behaviors hold clues about what out common ancestor looked like. Lemurs have four fingers and a thumb on their hands, and five toes on their feet, just like humans do. They have eyes and jaw bones that are similar to humans as well, but they have a wet nose, like a dog. Lemur behavior is also comparable to human behavior, as they live in social groups. Like apes and humans, lemurs travel together, groom one another, fight each other, and play together. Lemurs, however, have simpler friend and family relationships. Recently, lemurs have been studied in captivity. Like their distant chimpanzee and monkey cousins, they can be taught to use tools and to solve complicated problems. The word lemur means ghost. While the name probably comes from their huge reflective eyes and their strange, haunting cries, lemurs are ghosts in a way. They are living ghosts that remind US where we came from, and also give US clues about how humans evolved.
10. Why does the writer say: "they are living shosts" in paragraph 6?
