Fascinating Insights into Love, Evolution, and Mysteries of Nature

PPT Reader s Bank Level 7 Unit 09

25 _1 / p. 84 Reader s Bank Level 7 We have happy and wonderful feelings when we fall in love. Have you ever wondered why those feelings do not last forever? The answer lies in a chemical called nerve growth factor (NGF) in our brains. ( ) According to some Italian scientists, this chemical makes us feel very romantic in the beginning. ( ) When we first fall in love, levels of NGF increase, but that chemical fades over time. After a year or so, when we become more secure in a relationship, NGF levels drop. ( ) The researchers analyzed 58 volunteers who had recently fallen in love. ( ) They compared

25 _2 / p. 84 Reader s Bank Level 7 their levels of NGF with those of people who were single or in long-term relationships. ( ) In addition, they learned that NGF caused sweaty hands and nervous stomachs. Perhaps it is this chemical that makes young men buy their girlfriends red roses and candlelit dinners! They found increased levels of NGF in the people who just started their relationships.

26 ?!_1 / p. 86 Reader s Bank Level 7 The first life on Earth was a single-celled bacteria. For over a billion years, this single-celled bacteria evolved into various organisms, including fish, reptiles, mammals and humans. (A) When a big bacteria swallowed a small bacteria, the small one refused to be digested and begged for its life. But the big bacteria didn t want to listen. So, the small bacteria proposed a deal to the big bacteria: the small bacteria would become a part of the big bacteria s body and work for it like a servant. The big bacteria accepted the small bacteria s proposal, and that is how they came to together.

26 ?!_2 / p. 86 Reader s Bank Level 7 (B) How did this evolution happen? It happened in the process of bacteria competing and cooperating with one another for survival. For example, three billion years ago, bacteria on Earth fought and tried to eat each other. In this struggle for survival, an interesting thing happened. (C) The small bacteria transformed itself into an organ and became a part of the big bacteria s body. This organ is what we now call mitochondria. As you may already know, a mitochondrion is an internal organ of an animal that produces energy by burning nutrients. This is how a single-celled bacteria evolved into a mitochondria. , an animal with

27 _1 / p.88 Reader s Bank Level 7 There is a very interesting hill on Jeju Island called Dokkaebi Road. If you park your car in the middle of the hill, it will slowly go up the slope by itself. Surprisingly, Korea isn t the only country with a hill like this. In Maryland, U.S.A., there s a place called Spook Hill. If you park your car at the bottom of this hill, it rolls up just like the one on Jeju Island. According to legend, this was where one of battles of the Civil War took place. Many soldiers died here. People believe that the ghosts of the soldiers push their cars up the hill. That is why the hill is known as Spook Hill.

27 _2 / p.88 Reader s Bank Level 7 Are these hills really haunted? A research team conducted a study on Spook Hill. When they placed a measuring device on the hill, it pointed downward, which means it is downhill. So, although it looks uphill, it is actually downhill. Then why does a downhill road look like an uphill road? Scientists say it s a kind of optical illusion. The illusion occurs because you can t see the horizon from where you are. Also, the surrounding landscape makes the hill appear to be going up. So when you think your car is going up, it s actually . The next time you see one of these ghost hills, don t believe the local legend. There are no ghosts. It is only an optical illusion.