31、The undersea world is very beautiful. Now more and more people want to dive in the water to find the secrets there. Scuba（戴水肺） diving is a new sport today. It can take you into a wonderful undersea world.
You will find many strange animals in the sea. Some are like a school bus. Many sea animals give out light in the dark and some have sharp teeth.
During the day, there is enough light. Here, under the sea, everything is blue and green. When fish swim nearby, you can catch them with your hands. When you have bottles of air on your back, you can stay in deep water for a long time. However, you can't dive too deep. And you must be very careful when you dive in deep water.
The deep sea is not an easy place to live in. It is cold, and it is dark, too. The deeper it is, the less sunlight there is. At about 3,000 feet, there is no light at all. It is very dark in the sea. Many fishes have no eyes. Some have big eyes. A few have eyes on one side.
Besides the coldness and the darkness, deep-sea animals face a third danger - other animals.
Animals eat! They must find food to eat. Many animals eat plants. However, some animals eat meat. This means these sea animals have two big jobs. They need to find animals as food, and they have to try not to become other animals' meal.