问题 解答题

食物在消化腔内进行消化叫细胞内消化.(是/否)______.

答案

消化可分为细胞内消化和细胞外消化.单细胞动物如草履虫摄入的食物在细胞内被各种水解酶分解,称为细胞内消化.多细胞动物的食物由消化管的口端摄入在消化腔中消化叫做细胞外消化.在高等动物(如人)的体内,仍部分保留着细胞内消化,如白细胞吞噬体内异物并在细胞内把异物溶解等.

细胞外消化主要是:食物在各种消化液作用下,因为消化液里消化酶,可以把食物裂解为更小的可以被细胞吸收的物质.

细胞内消化主要是:在溶酶体酶的作用下,把一些物质进一步的分解掉.溶酶体就相当于是细胞里的消化器官.

故答案为:否

单项选择题
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Most mornings, the line begins to form at dawn: scores of silent women with babies on their backs, buckets balanced on their heads, and in each hand a bright­blue plastic jug. On good days, they will wait less than an hour before a water tanker goes across the dirt path that serves as a road in Kesum Purbahari, a slum on the southern edge of New Delhi. On bad days, when there is no electricity for the pumps, the tankers don't come at all. “That water kills people,” a young mother named Shoba said one recent Saturday morning, pointing to a row of pails filled with thick, caramel (焦糖)­colored liquid. “Whoever drinks it will die.” The water was from a pipe shared by thousands of people in the poor neibourhood. Women often use it to wash clothes and bathe their children, but nobody is desperate enough to drink it.

There is no standard for how much water a person needs each day, but experts usually put the minimum at fifty litres. The government of India promises (but rarely provides) forty. Most people drink two or three litres—less than it takes to wash a toilet. The rest is typically used for cooking and bathing. Americans consume between four hundred and six hundred litres of water each day, more than any other people on earth. Most Europeans use less than half that. The women of Kesum Purbahari each hoped to drag away a hundred litres that day—two or three buckets' worth. Shoba has a husband and five children, and that much water doesn't go far in a family of seven, particularly when the temperature reaches a hundred and ten degrees before noon. She often makes up the difference with bottled water, which costs more than water delivered any other way. Sometimes she just buys milk; it's cheaper. Like the poorest people everywhere, the people of New Delhi's slums spend a far greater percentage of their incomes on water than anyone lucky enough to live in a house connected to a system of pipes.

小题1:The underlined word “slum” most likely means________.

A.a village

B.a small town

C.an area of a town with badly­built, over­crowded buildings

D.the part of a town that lacks water badly小题2:Sometimes the water tanker doesn't come because________.

A.the weather is bad

B.there is no electricity

C.there is no water

D.people don't want the dirty water小题3:A person needs at least________litres of water a day.

A.a hundred

B.four hundred

C.forty

D.fifty小题4:Which of the following statements is WRONG?

A.A hundred litres of water a day is enough for Shoba's family.

B.Americans uses the largest amount of water each day.

C.In Kesum Purbahari milk is cheaper than bottled water.

D.Shoba has a family of seven people.