The author believes the theories of aging are
Câu hỏi
Nhận biếtRead the following passage, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.
There are many theories of aging, but virtually all fall into the category of hypotheses with a minimum of supporting evidence. One viewpoint is that aging occurs as the body ‘s organ systems become less efficient. Thus failures in the immune system, hormonal system, and nervous system could all produce characterisitics that we associate with aging. Following a different vein, many current researchers are looking for evidence at the cellular and sub cellular level. It has been shown that cells such as human fibroblasts (generalized tissue cells) grown in culture divide only a limited number of times and the die. Only cancer cells seem immortal in this respect. Fibroblast cells from an embryo divide more times than those taken from an adult. Thus some researchers believe that aging occurs at the cellular level and is part of the cell ‘s genetic makeup. Any event that disturbs the cell ‘s genetic machinery such as mutation, damaging chemicals in the cell ‘s environment, or loss of genetic material, could cause cells to lose their ability to divide and thus bring on aging. Other theories of aging look at different processes.
Chronological aging refers to the passage of time since birth and is usually measured in years. While chronological age can be useful in estimating the average status of a large group of people, it is a poor indicator of an individual person ‘s status because there is a tremendous amount of variation from one individual to the next in regard to the rate at which biological age changes occurs. For example, on the average, aging results in people losing much of their ability to perform strenuous activities, yet some elderly individuals are excellent marathon runners.
Another type of aging is cosmetic aging, which consists of changes in outward appearance with advancing age. This includes changes in the body and changes in other aspects of a person ‘s appearance, such as the style of hair and clothing, the type of eyeglasses, and the use of a hearing aid. Like chronological aging, it is frequently used to estimate the degree to which other types of aging have occurred. However, it is an inaccurate indicator for either purpose because of variation among individuals and because a person ‘s appearance is affected by many factors that are not part of aging, including illness, poor nutrition, and exposure to sunlight.
The author believes the theories of aging are _________
Đáp án đúng: B
Lời giải của Tự Học 365
Giải chi tiết:
Đáp án là B. Dựa vào ý đầu tiên trong bài: There are many theories of aging, but virtually all fall into the category of hypotheses with a minimum of supporting evidence.
Luyện tập
Câu hỏi liên quan
-
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
Peter bought a car as a present for his wife two weeks ago.
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
There has been growing public concern about the use of chemicals in food recently.
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
The higher the cost of living is, .
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
The success of the company in such a market is remarkable.
Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions.
Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
Harmful environmental factors can the development of certain diseases.
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
A lot of research in medical science has been to improve human health.
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
Last week, we an interesting film about the animal world.
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
The dog my father gave me is very lovely.