This wonderful animal world
Animals live all over the world. They walk or crawl on land, fly in the air and swim in the water. Dogs, horses, sparrows, frogs, and worms are all animals. So are butterflies, goldfish, elephants, cockroaches, and snakes.
Animals may be of many shapes and sizes and some of them do not even look like animals. Many water animals look like plants growing on the rocks or in the sand under the water.
Plants and animals are different from each other in two important ways. First, plants cannot move by their own power as animals can, and, second, animals cannot make their own food as plants do.
There might be some doubt about a sponge. Is it an animal or a plant? The sponge does not fit the rule because it cannot move. Yet it is an animal because it does not make its own food. It lives by feeding on small animals in the water.