With the development of technology, WiFi is becoming more and more popular and important in people's daily life. But have you ever experienced it? Just imagine what life will be like if there is no Internet. Maybe you won't be able to talk with friends, play video games or search for information for your homework on the Internet.

    But in fact, only one third of the world's population are able to get information on the Internet. The rest are too poor to buy WiFi access(使用权) or they live in remote areas. As a result, they live without the Internet.

    Google and Facebook, two world-famous technology companies, have decided to do something about it. Google's Project Loon will try to send balloons which are 15 meters wide into our Earth's stratosphere (平流层) in 2015. The balloons are made of a special material that is three times thicker than the plastic bag we use every day. Each balloon will carry a minicomputer and a WiFi radio. The WiFi radio will send the Internet over the areas it is floating over. Then people can get up-to-date information on weather or news.

 Monarch butterflies from eastern Canada make the most amazing journey in the insect world. Each year, this butterfly travels about 3000miles to its winter home in central Mexico(墨西哥). How can it fly so far? And why does it make this long and dangerous trip? Scientists still don't have an answer.

 For many years, people in Mexico wondered where the orange-and-black butterflies came from every winter. Then, in 1937, a scientist started to follow and study the butterflies. For the next 20 years, he discovered that one butterfly started its journey in Canada. Four months later, it arrived in Mexico.

 The length of the butterflies find their way back to the same place? Another amazing thing is that the butterflies always return to the same area in central Mexico.

 How do the butterflies find their way back to the same place? This is an interesting question because only every fourth generation(代) makes the trip south. In other words, the butterfly that travels to Mexico this year is the great-great-grandchild of the butterfly that traveled there last year.

 Each year, four generations of a Monarch butterfly family are born. Each generation of the family has a very different life. The first generation is born in the south in late April. It slowly moves north, reproduces(繁衍), and then dies. On the trip north,two more generations are born, reproduce, and die. Each of these generations of butterflies is born. This generation has a much longer life. It lives for about eight months. This generation of butterflies makes the amazing journey back to the winter home of its great-great-grandparents. The butterflies spend the winter there, and in the spring they reproduce and then die. Their offspring will be the first generation of the next circle of life.

 Today, people are still studying the Monarch butterfly. But they are not clear about everything.

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    Do you have brown hair? Are you taller than other kids your age? These characteristics were decided before you were born. You got your traits from your parents. They passed their traits on to you through genes (基因).

    Genes carry codes (代码) for blue eyes or brown eyes. Genes say how tall you will get and what color hair you will have. You got half of your genes from your mother. You got half of your genes from your father. So you have your own set of genes. Each person gets different genes for each body part. That is why you look like but not exactly like your brother or sister.

    A dominant (显性的)  gene shows up most of the time. Brown eyes are dominant over bluc eyes. A recessive (降性的)  gene shows up less often. Light hair comes from a recessive gene. Dark hair is more common. Look at the eye color and hair color of the people around you. You will see that this is true.

    Genes help to make you who you are. But they don't tell the whole story. Your genes may help you to be fast and strong. But you still need to learn how to run or swim or skate well.