Why do plants grow in some places and not in the others? Why does some land have so much growing on it, while other land has almost no plants growing on it at all?

    To grow, plants need several things. One is warmth. In very cold places almost nothing grows. Plants also need water. In very dry parts of the Earth only a few unusual plants can grow. That's why dry deserts everywhere are almost not covered by trees or grass.

    Plants must also have a place in which to put down their roots and grow. They find it difficult to grow on hard land. The town is built on hard land. The plants here have only the soil found between the cracks of the stones to grow in.

    Another thing plants must have before they can grow is food.

What will happen if we try to make things grow on the sandy beach? A few plants, such as beach grass, will grow in sand, but most plants won't. Even if the weather is warm enough and we water the plants each day, many of them will die because the sand on this beach has almost no food for plants.

    In the most southern part of our planet, there's a place that's covered with snow and ice all year round. But it has the clearest and cleanest air. Amazingly, in this place, the sun sometimes hangs even in the midnight sky. This place is Antarctica (南极洲): the coldest, windiest and harshest (恶劣的) place on the Earth.

    As the world's least-known place, Antarctica is of great interest to scientists around the world. During 30 years, China has sent many scientists to Antarctica. They mostly look at the resources under the icy land and do research about climate change and marine (海洋的) biology.

    Antarctica is a place with fantastic views. However, life there is very hard. Food is one of the biggest problems. Frozen food which can be heated easily is people's daily food. Fresh vegetables are hard to grow in the cold weather.

    Sleep is also difficult. In Antarctica, summer lasts from November to March. During this period, Antarctica points to the sun and receives sunlight 24 hours a day. In order to get some sleep, scientists cover the windows with black plastic cloth to create "night".

    Working in Antarctica is dangerous, especially when meeting gale-force (七级以上的) winds. They can easily blow people away. So there are ropes that connect buildings of some research stations. People can hold these ropes to keep their balance in forceful winds.

    What's morel communicating with others is difficult. Without cables and Internet in some research stations, two-way radios are the only tools to communicate. If people want to say hello to friends and relatives, they can use satellite phones.

    Although it is challenging to work in Antarctica, scientists' passion to learn about this mysterious land will never end. It is hopeful that one day they will step every corner of this icy land.

    With the development of the technology, 3D printing is becoming more and more popular. We are now able to print things such as clothing, musical instruments and even cars. People and businesses are able to create the things they need very quickly and easily by using 3D printers.

    But can you imagine printing food? Some scientists are trying a new way to get the dining experience by doing this. They hope that having a 3D printer in the kitchen will become as common as the oven or blender. Scientists say that they are easy to use: you simply have to choose a recipe (食谱) and put the uncooked "food ink" into a printer. You can also change the instructions to make the food you want. This means that it would be very quick and easy to create tasty and rich meals.

    Using 3D printers to create your meals would also be saving the environment. There would be less need for traditional growing, shipping and packaging processes as food products would be a lot quicker and better. For example, tree leaves and insects could be turned into tasty products! Printing food could also help people who have a swallowing (吞咽) trouble. They could program the printer to print softer kinds of foods so that they would not have difficulty swallowing them.

            It could take away many jobs, including those for growing, shipping and packaging food. Imagine a world where there was no need for growing or producing and the same tastes could be printed from an uncooked "food ink". Besides, traditional restaurants might lose business. Also, we have to consider: is it really possible to get everything we need from them?

    As we know, cooking and eating together with family and friends has long been a traditional and enjoyable activity. It is hard to imagine a world where the pastime of cooking is dead and meals can be created at the touch of a machine.

    There are many wetlands in China and some of them have become the world's important wetlands. The Chinese Yellow Sea Wetlands are among them. They are in Yancheng, Jiangsu Province. They are home to many different kinds of animals. The world's largest Milu Deer Nature Reserve is in them. More than 700 Milu deer live freely there. There are not many red- crowned cranes in the world, but every winter you can see some in the Red-crowned Crane Nature Reserve in the Yellow Sea Wetlands.

    The temperature in the wetlands is usually neither too high nor too low. There is a lot of rain and sunshine too. They are really good places for wildlife. Offering(提供) food and home to some special kinds of animals is not the only reason why we need to protect wetlands. Wetlands are important because they also prevent flood. But some people want to change the wetlands to make more space for farms and less space for wildlife.

    Luckily, more and more people are beginning to realize the importance of wetlands and wildlife. Every year, on February 2nd, many activities are held to tell people more about wetlands.

    What is an egg? Birds and fish give birth to many babies at one time. They can do this by laying (产) many eggs. The baby birds or the baby fish stay in eggs until they are ready to be born. What do eggs look like? When you make a fried egg, you can see a yellow part and a white part. The yellow part of the egg becomes a chick. The chick eats the white part until it comes out of the egg.

    What is a fruit? Why do plants have fruits? A fruit is the house of seeds (种子). Plants grow flowers to make fruits. Fully grown fruits fall down. Then, the seed grow root (根) under the ground. What happens next? Another plant grows! Usually seeds grow inside of a fruit, but strawberry seeds grow outside of the fruit.