II. Read the paragraph and answer the questions that follow Birds are very light. Their bones hollow. They anasehaninskas. Their bones are light, too. Even the bones of their skull are almost weightless. That is why birds can fly 1. What is talked about in every sentence? 2. What does the whole paragraph tell about birds? 3. Which sentences give details about the paragraph? 4. What do you call this sentence? 5. In the given passage, where is the key sentence found?​