The deep sea is not an easy place to live in. It's cold and dark. The deeper it is, the less sunlight there is. At about 3,000 feet, there is no light at all. It's very dark in the sea. Many fishes have no eyes, but some have big eyes. A few have eyes only on one side. Besides the coldness and the darkness, deep sea animals face a third danger--other animals. Animals must find food to eat. Many animals eat plants, and some eat meat. This means these sea animals have two big jobs. One is that they need to find animals as their food, and the other is that they have to try not to become other animals' meals. ,. (5) Sea animals have two jobs. They  _  .
swim and find food find friends and eat other animals need to find animals and make friends need to find animals as food and have to try not to become other animals' meals.