问题 选择题

青少年处在生长发育的关键时期,每天需要补充一定量的蛋白质。下面有关蛋白质在人体内作用的叙述,不正确的是

A.是构成人体细胞的基本物质

B.是人体进行生理活动的主要能源

C.能为人的生理活动提供能量

D.是组织生长、修补和更新的主要材料

答案

答案:B

食物中含有六大类营养物质:蛋白质、糖类、脂肪、维生素、水和无机盐,它们的作用不同:蛋白质、糖类、脂肪能为人体提供能量,其中蛋白质是构成人体细胞的基本物质,与人体的生长发育以及细胞的修复和更新有重要关系,糖类是人体最主要的供能物质,脂肪是人体内备用的能源物质,,无机盐是构成人体组织的重要原料,水是细胞的主要组成成分,人体的各项生命活动都离不开水,人体内的营养物质和废物都必须溶解在水里才能进行运输,维生素对人体的各项生命活动有重要的作用,水、无机盐、维生素不提供能量。

选择题
单项选择题

The questions in this group are based on the content of a passage. After reading the passage, choose the best answer to each question. Answer all questions following the passage on the basis of what is stated or implied in the passage.

Of all aspects of Indian culture, the caste system is perhaps the most bewildering to outsiders. For visitors unaccustomed to this system of hereditary social divisions, the complex and mostly unwritten rules governing whom a person can marry, what kind of work she can do, and even what kind of food she can eat may seem puzzling and mysterious. One reason for this confusion is that the concept of caste is actually divided into two separate but related concepts in Indian culture: varna and jati.

Varna, which literally means "color," is the most basic social division. There are four varna: the Brahmans, the traditional priest class; the Kshatriya, the warrior class; the Vaishya, the skilled workers and merchants; and the Sudra, laborers whose role is to serve the three higher classes. Below the Sudra are a class known as the Untouchables, who technically fall outside of the varna system because they are supposedly "unclean" in a ritual sense. The Untouchables are the lowest class in India, but they make life possible for everyone else because they take care of the jobs that would "pollute" the higher classes, such as working with dead animals or cleaning sewage. The Indian statesman Mohandas Gandhi, in an effort to promote social equality, encouraged people to refer to Untouchables as the Harijan, which means "Children of God."

Each varna is then divided into hundreds or thousands of jati, a term that literally means "birth." The jati are kinship groups with hereditary roles and professions, such as leatherworker or brick-maker. Observant Hindus have traditionally married within their varna and jati.

The origins of the caste system are obscure. The prevailing theory among anthropologists is that the Varna system emerged shortly after the so-called Aryan Invasion of the second millennium B.C. According to this theory, a population of Indo-European invaders conquered northern India around 1500 B.C. The Indo-Europeans placed themselves in the three highest rungs of society (Brahman, Kshatriya, and Vaishya), corresponding to the traditional division of Indo-European societies into priests, warriors, and commoners, while placing the conquered local populations into the worker classes of the Sudra and the Untouchables. This theory does not account for the jati system, however, which has parallels in no other Indo-European society. Most anthropologists suggest that the jati system predates the varna system, and that it might have originated in the Harappan civilization that prevailed in northern India prior to the Aryan Invasion.

What inference could reasonably be drawn from the second to last sentence of the passage ?()

A. Unlike the situation of the jati, parallels can be found between the varna system and the social divisions found in other Indo-European societies.

B. The jati system is actually a product of the Dravidian cultures of central and southern India.

C. Although more anthropologists support the Aryan Invasion theory than support any other explanation for the origins of the caste system, a majority of anthropologists do not believe this theory.

D. The jati system, unlike the varna system, developed after the influence of Indo-Europeans in India had already been established.

E. The Sudra did not willingly accept the low-caste jati to which they were assigned, but these social roles were forced upon them anyway.