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Reader's Bank_Level 5_Unit 09                                    Reading Text

A cell is the smallest unit of an animal’s body. In your body, there are an enormous number of cells. Cells grow, change, and even get sick, just like humans. But did you know that cells can die to help others? When does this happen? Some cells die to get rid of useless body parts. For example, tadpoles have tails. As they become frogs, they no longer need them. So, the tail cells die, and the tails disappear. Other cells die because they are damaged or infected. Sick cells don’t want to affect healthy ones. For instance, a cell can get infected by a virus. Then, the cell chooses to die, which helps stop the virus from spreading. In this way, cells die to keep our bodies healthy and safe— like tiny bodyguards keeping us safe!

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Tim eats a lot, but he is still thin. Bill eats just a little, but he is overweight. Why is that? A professor conducted an experiment with Tim and Bill to find out. He asked them to lie in bed for one whole day. They did nothing but breathe. After that, the professor checked how many calories they had burned. He was surprised by the results. Tim had burned 3,네015 calories, but Bill had burned only 1,067. The reason was their genes. Tim was born with genes that help him burn lots of calories, but Bill was born with genes that make his body burn fewer calories. Even if you’re like Bill, don’t worry! Your genes don’t change, but your habits still affect cause them. If you eat well and exercise, you can stop the “fat genes” from being active. It’s like turning off a light switch. Good habits can keep you healthy.

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Dubai is a desert city. It doesn’t rain much—less than 4 inches a year. Water is very important there. But global warming is making the water problem worse. To solve this problem, Dubai is using drones to make rain. The idea of artificial rain isn’t new, but Dubai is the first to use drones to create it. The drones f ly into the sky to find clouds. When they find clouds, they send small electric shocks, like fake lightning. This makes tiny drops of water stick together and become bigger drops. When the drops become heavy enough, they fall as rain. The size of the drops is very important. If the drops are too small, they dry up before they hit the ground because the air is hot and dry. In the past, people used chemicals to make rain, but this hurt nature. Using drones is safer for the environment. Now, other countries want to use drones to make rain too. Soon, drones might help us make rain whenever we need it!