Throughout history man has had to accept the fact that all living things must die, but people now live longer than they (36) . Yet, all living things still show the (37) of aging, which will eventually. (38) death.
Aging is not a disease, but as a person passes maturity, the cells of the body and the (39) they form do not function as well as they (40) in childhood and adolescence (青春期). The body provides less (41) against disease and is more prone (42) accident.A number of related cause may (43) aging. Some cells of the body have a fairly long life, but they are not (44) when they die. As a person ages, (45) of brain cells and muscle cells decrease, (46) body cells die and are replaced by new cells. In an aging person the (47) cells may not be as viable (能生存的) or as capable (48) growth as those of a young person.Another (49) in aging may be changes within the cells (50) . Some of the protein chemicals in cells are known (51) with age and become less elastic. This is why the skin of old people wrinkles and (52) . This is also the reason old people (53) in height. There may be other more important chemical changes in the cells. Some complex cell chemicals, such as RNA, store and (54) information that the cell need. Aging may affect this (55) and change the information carrying molecules so that they do not transmit the information as well.
A.to
B.for
C.against
D.in
延伸阅读
你可能感兴趣的试题
My husband and children feel very happy to live here. They can’t see that we live on a dirty street in a dirty house among people who aren’t good. They can’t see that our neighbors have to make happiness out of all this dirt. I decided that my children must get out of this. The money that we’ve saved isn’t nearly enough.
The McGaritys have money but they are so proud. They look down upon the poor The McGarity girl just yesterday stood out there in the street eating from a bag of candy while a ring of hungry children watched her. I saw those children looking at her and crying in their hearts; and when she couldn’t eat any more she threw the rest down the sewer (下水道). Why Is it only because they have money There is more to happiness than money in the world, isn’t there
Miss Jackson who teaches at the Settlement House isn’t rich, but she knows things. She understands people. Her eyes look straight into yours when she talks with you. She can read your mind. I’d like to see the children will be like Miss Jackson when they grow up.
A. money is the most important thing
B. there is something more important than money
C. we should look into their eyes while talking to people
D. the more money you have, the less happy you would be
Every year gray whales migrate from the Bering Sea in Alaska to the Baja Peninsula in Mexico.
Eleven gray whales have died in the San Francisco Bay in the last three weeks. No one knows why the whales are dying.
Last year 270 whales died along the whales’ migration route. Many people think starvation is the cause. This year the dead whales seem to have more blubber (fat) on them.
Twenty years ago, the gray whale was listed as an endangered species.
Some scientists think that the larger number of whales makes it hard to find enough food. More whales create more pressure on the food supply, a supply that some scientists say may have dwindled as a result of the warm waters of El Nino.
Most of the whales have been dead for many days before they are found and studied. This makes it hard to find the reason for death.
65 whales have been seen in the San Francisco Bay Area this year compared to 17 last year. The whales could be dying from many diseases, but it may be over-population.
A. the whales travel such a long distance
B. there are more whales than there used to be
C. the whale bodies are too old to study by the time they are found
D. the whales are endangered
热门相关试卷
最新相关试卷