There are many kinds of animals that live in the forest, such as mice, rabbits, squirrels, bears.

    Animals in the forest depend on（依靠）one another for food. Many small forest animals, such as mice, eat green plants for food, and then larger animals eat them. This is called food chain. A food chain begins with the sun. The green plants in the forest use the sun's energy to make food for themselves. It's called photosynthesis(光合作用). Mice eat flowers and seeds that forest plants produce(生产).The mice get their energy from the plants, and the mice become food for a larger animal, such as the hunting hawk. So the energy from the sun passes from the plants to the mice to the hawk. A break（中断）in any part of this food chain means some animals may not have enough food to eat.

    In nature, you may see many insects(昆虫) and animals of different colors. Have you ever wondered why?

    Locusts are super delicious food for birds, but it is not always an easy job for birds to catch them. It is neither because locusts are good jumpers or runners nor because they are smarter than their enemies. The reason is that the colors, of locusts change with the colors of crops(庄稼). When crops are young, locusts look green. But when autumn comes, locusts change to the yellow and brown color as crops do.

    Brown bears, tigers and other animals move quietly through forests. They can't be seen easily by their enemies. This is because they have colors similar to the trees. For the same reason, polar bears that live on a land of snow and ice are white. Butterflies and bees living among the flowers are colorful like flowers. Soil insects are mostly dark colored and they live under the soil(土壤)in a dark and wet environment. However, insects with colors different from plants can easily be found and eaten by others. So in order to survive, they have to hide themselves in the daytime and appear only at night.

    Have you ever noticed some even stranger acts? The ink fish in the sea can send out some very black ink when it faces danger. As the ink spreads over, its enemies will find themselves suddenly in a dark world. At the same time the ink fish immediately swims away. That is how it keeps itself safe though it is not strong at all.

    What should you do if there's an earthquake at school? How can you protect yourself when you are caught in a stampede(踩踏)?March 28, 2016 provided you with a good chance to learn about safety.

    This day was called the National Day of Education on the Safety of Elementary and Middle School Students(NDESEMSS)(全国中小学生安全教育日). The theme of the day was to give students more knowledge about safety and make sure their lives are safe.

    A survey done by the China Youth and Children Research Center showed that school accidents kill more elementary and middle school students than anything else. The main accidents come from stampedes, earthquakes, fires and sports injuries(伤害).

    What can we do to keep ourselves safe? Staying calm is the first and most important rule when facing accidents. But different accidents have different self-protection advice.

    A stampede is possible anywhere. The larger a crowd gets, the more likely stampedes become. When students around you begin to push, stand still and try to hold onto something, or stay in a corner until the crowd leaves. If you fall down in a moving crowd, cover your head with both hands. Lean to(偏向) one side, curl up(蜷缩) your body and bend your legs.

    Earthquakes are common natural disasters(灾难). When you feel the ground shake, drop down, take cover under a desk and hold on. You should stay indoors until the shaking stops. If you are outdoors, don't stay near buildings, trees or power lines.

    When there's a fire, follow the teachers' instructions, leave the classroom quickly and use a piece of wet cloth to cover your mouth and nose so that you don't breathe in smoke.