Could smells affect your lifespan? Female fruit flies rid of the ability to smell food outlive their peers.The sense of smell may be linked to the cellular ageing process in many other organisms--even people.A link has recently been found between sensory experiences and lifespan in both worms and flies.For example, Scott Pletcher, a biologist at the University of Michigan, found that eliminating fruit flies' ability to smell enabled them to live nearly 20 percent longer than flies with an intact sense of smell. Pletcher's team reasoned that food smells were the ones most likely to affect ageing, as nutrition and longevity are known to be linked in many organisms.To test the idea that food odors affect lifespan, Pletcher's team eliminated flies' ability to smell carbon dioxide, which is produced by some fly foods.They left the rest of the smelling system intact. This intervention had no effect on male flies, but the females lived 30 percent longer than normal.Pletcher thinks eliminating the ability to smell CO2may deprive flies of information about food availability.This could signal to cells that food is scarce, causing processes that promote survival.Indeed, his team found that the CO2-insensitive female flies stored extra fat and that both males and females immune to CO2were more resistant to stress than normal flies.Pletcher isn't sure why the change in his fruit flies only affected the lifespan of the females, but he suggests that females may simply be more sensitive to the odor of CO2. A smell or taste that stretches lifespan in humans could be a potential preventative for age-related disease, he adds.Although in fruit flies it appears to be the smell of CO2that affects ageing, he says that an analogue in humans might be a smell or taste linked to human food--or a lack of it.Matt Kaeberlein studies ageing at the University of Washington in Seattle. He cautions that we don't know whether ageing and smell are linked in mammals.But " we definitely undergo physiological changes in response to smelling... The purpose of the study by Scott Pletcher is to _ . A) show there is the best way to make lifespan longer B) tell us we should eliminate our smell ability to live long C) show the sense of smell can affect the cellular ageing process D) explain female fruit flies without ability to smell odor can live longer
C
Mr. Peter Johnson, aged twenty-three, battled for half an hour to escape from his trapped car yesterday when it landed upside down in three feet of water. Mr. Johnson took the only escape route -- through the boot . Mr. Johnson's car had finished up in a ditch at Romney Marsin, Kent after skidding on ice and hitting a bank."Fortunately, the water began to come in only slowly", he said. "I couldn't force the doors because they were jammed against the walls of the ditch and dared not open the windows because I knew water would come flooding in." Mr. Johnson, a sweet salesman of Sitting Home, Kent, first tried to attract the attention of other drivers by sounding the horn and hammering on the roof and boot. Then he began his struggle to escape. Later he said, "It was really a half penny that saved my life. It was the only coin I had in my pocket and I used it to open the back seat to get into the boot. I hammered desperately trying to make someone hear, but no help came." It took ten minutes to open the seat, and a further five minutes to clear the sweet samples from the boot. Then Mr. Johnson found a tool and began to work on the boot lock. Fifteen minutes passed by."It was the only chance I had. _ , but as soon as I moved the boot lid, the water and mud poured in. I forced the lid down into the mud and climbed out of my car as it filled up." His hands and arm cut and bruised, Mr.Johnson got to Beckett Farm nearby, where he was looked after by the farmer's wife, Mrs.Lucy Bates. Covered with a blanket, he said,"That thirty minutes seemed like hours.""Only the tips of the car wheels were visible,"police said last night. The vehicle had sunk into two feet of mud at the bottom of the ditch." It can be inferred from the passage that _ . A) the police helped Mr. Johnson get out of the ditch B) the accident happened on a clear warm day C) the ditch was along a remote country road D) Mr. Johnson had a tender wife and was well attended
C
Q: Tigers are the largest wild cats in the world. They usually go out to hunt for food when it is dark. When a tiger sees an animal, it moves quickly and then jumps on the animals to kill it. Sometimes it can take the tiger several days to finish eating its food. When the tiger is full, it will cover the dead animal with leaves. Later, when the tiger is hungry again, it comes back to eat some more. Tigers are different from others in the cat family: they like water and often jump into rivers to swim. Some tigers live in very cold places in North Korea, Russia and China. Other tigers live in warmer places--in India and parts of Southeast Asia. But now all tigers are in danger. Some people kill tigers to use their skins for clothes, and their bodies for medicine. There is also less and less land for tigers to live in. ,. Tigers are in danger now because _ . A) some people kill them B) the weather becomes warmer C) they have less land to live in D) both A and C
A: D
In 1996 I wanted to buy a Honda Civic. I went to the local dealer. "Oh, you want a Civic, do you?" said the fellow. "And I suppose you'd also like us to throw in a couple of front-row Superbowl tickets? Haw! Haw! Haw! Haw!" When his laughter ended, he explained that the Civic was such a hit in Europe that Honda was getting an extra $ 2,000 per car there, making Civic practically unavailable in the States. But he did offer to let me add my name to the waiting list--if I agreed to pay $1,000 over the sticker price. When Honda dealerships No. 2 and No. 3 gave me the same story, I was ready to try anything. I carefully looked over to www.autobytel.com. For a _ like me, Auto-By-Tel's scheme is nearly irresistible. You indicate the car you want to buy, compete with the freedom to choose. The nearest participating car dealer mails you back with a cut rate offer. There's no charge for any of this -- and no obligation to accept the offer. It surely seemed no less to me. Sure enough, two days later, a dealer 30 minutes away wrote me. "Unfortunately, 96 Civics are in very short supply," his message said, "The best we can offer you is $1,200 under sticker price. "I was in happiness. Ah! Bliss! Ah, saving! Ah, revenge! When I picked up the car, it got better. Since there was no haggling , the dealership fellow was friendly and congratulatory instead of everything. Now this, I thought, is the way to buy a car. Auto-By-Tel makes money by charging a fee to each participating dealer. The dealers make money by receiving hundreds of ready-to-buy customer names off the Web. And you save money because your price doesn't reflect advertising, test drives, sales commissions, and so on. My only regret is that I didn't think up Auto-By-Tel first. What do you think of the Auto-By-Tel? A) It makes money by not giving taxes. B) It is good at advertising. C) It is good at the business. D) It makes money by cheating customers.
C