21. Read the text. Choose the right words and write them on the lines. Whales are sea animals that look like very big fish. But whales are different from fish because their babies stay with their mothers and drink their mother's milk for a year or more. Whales are also different 1…………… fish because they have to swim up to the top of the water to take air in every 30 or 40 minutes. There are two different kinds of whale hales with teeth and whales without teeth. One kind of whale that doesn't have teeth is the Blue Whale. Blue Whales are the 2…………… animals in the world, but they only eat very small sea animals. These are 3……….. "krill". Dolphins are a kind of whale with teeth. They eat fish and live in family groups. They learn quickly and people 4…………. swim with dolphins never forget them because they are very clever, friendly and beautiful. Whales have strange songs which they whistle or sing under the water. These songs are very loud. The whole is noisier 5…………… all other animals. 1. From of to for 2. Bigger biggest most big big 3. To call calling calls called 4. When who which whom 5. As or than from