Think about a world without insects (昆虫). It sounds nice at first. But in fact, this could be really bad news.

The number of insects is getting a lot smaller than before, a British biologist Dave Goulson said. “In the 27 years from 1989 to 2016, about 75% insects died.” Goulson wrote.

Scientists say the main reason for this is the use of pesticides (衣药). Theydestroythe places that insects live in. The insects lose their homes and food, so they die out day by day.

What would happen without insects? It’s almost impossible to tell, but the results would be far-reaching. We need insects to pollinate (给……授粉) plants. They also break down dead plants and animals and turn them into new useful things. We need them to keep the land healthy and do much more. Without insects, many animals would have nothing to eat. They would go hungry and die. Then the natural world will get worse and worse.

“We should stop using pesticides (农药), both for insects and ourselves. The first step is to let more people understand everything in the natural world is important for us.” Goulson said, “The best place to start is with our children. We should teach them to look after the natural world from an early age.”

①Plants have roots, leaves, and flowers. They have seeds (种子), too. New plants grow from seeds. Some seeds fall on the ground. New plants grow next to the old plants. When plants grow this way, they are too crowded to get enough sunshine and water. So some of them die. But some plants spread their seeds even far from where they live. These seeds grow in new places. There are many ways of the seeds’ travel.

②The wind helps seeds to travel. Some plant seeds have little wings. When the wind blows, the seeds fly away. Soon they fall to the ground and new plants may grow there. Some plants dry up. The wind pulls them from the ground, but they are so big that they can’t fly. They roll along the ground, dropping off their seeds.

③Other plants grow near the water. Their seeds drop into the water and go away with it. They may travel many miles before they stop.

④Some seeds have special parts called “stickers”. The stickers help the seeds travel far. How? These seeds wait for an animal to walk by. Then they stick into its fur to get a free ride. Sometimes it’s a long trip. Birds carry some plant seeds to new places, too.

⑤Seeds can’t walk. They can’t run. But they can travel with the help of wind, water and animals.

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A person comes towards you and says “hi”. But you have no idea who he or she is . If you often experience this, you may have face blindness (脸盲).

A new study showed that face blindness might be more common than we thought. One in 33 people may have it. Some have serious problems. They cannot even recognize friends or families. But some just have smaller problems. They spend a long time remembering faces. People could be born with face blindness, or develop it if they hurt their brain.

Face blindness sounds like just a small problem. But according to Joseph DeGutis, the writer of the study, people with it may have a bad social life. “Recognizing someone is a social signal. It means ‘you are important to me’,” DeGutis told Harvard Medicine News. Not recognizing others may lead to misunderstanding, and then fewer friends. Worry about recognizing faces may also make people stay away from social life.

Here are signs of face blindness. In films, you sometimes fail to tell the difference between characters. When a close friend changed their hairstyle, you couldn’t recognize them. When you meet a new group of people, it takes a long time before you can recognize each person. You’re not famous, but lots more people recognize you than you can recognize in return. If you see a person in two different places (for example in your school and in a shopping mall), you might think of them as two different people.

In the past, people paid little attention to this. The studies on face blindness only began in the 1990s. Today, more scientists and organizations are working to tell more people about face blindness and its effects on our social life.