描述动物特征的简单表达 — 英语阅读题

Read the passage and answer the question. My name is Ben. My friend Lily and I love animals. Lily likes penguins best. She says, "Penguins are birds, but they can't fly. They can swim very fast. They have short wings." I like kangaroos. Kangaroos have strong legs, so they can jump very high and far. They carry their babies in a pocket on their bodies. Lily and I often go to the zoo together and watch these animals. Question: Why can kangaroos jump very high and far? (Answer in English.)