问题 单项选择题

真菌的繁殖方式,不包括()。

A.芽殖

B.裂殖

C.产生孢子

D.有性繁殖

E.复制

答案

参考答案:E

解析:

真菌的无性繁殖方式可概括为四种:

①菌丝体的断裂片段可以产生新个体,大多数真菌都能进行这种无性繁殖,实验室“转管”接种便是利用这一特点来繁殖菌种。

②营养细胞分裂产生子细胞,如裂殖酵母菌无性繁殖就像细菌一样,母细胞一分为二地繁殖。

③出芽繁殖,母细胞出“芽”,每个“芽”成为一个新个体,酵母菌属的无性繁殖就是这种类型的繁殖。

④产生无性孢子,每个孢子可萌发为新个体。

单项选择题
单项选择题

Internet shopping is a new way of shopping. Nowadays, you can shop for just about anything from your armchair. All you need is a computer which is linked to the Internet. Shopping on the Internet is becoming increasingly popular. In the United States, people spent over US $2.5 billion on Internet shopping in 1998. This figure is expected to reach US $11 billion by the year 2004.
People can shop for a variety of products on the Internet. Physical products include items such as books, CDs, clothes and food. These types of products are the most common purchases through the Internet. You can also buy information products such as on-line news or magazine stories, or you can download computer software through the Internet. Services such as booking airline tickets, reserving hotels or renting cars are also available on the Internet. You can also go shopping on the Internet for entertainment services and take part in on-line games.
Internet shopping offers a number of benefits for the shopper. The most important advantage is convenience. You can shop when you like as the on-line shops are open 24 hours a day and you don’t have to queue with other shoppers at the checkout counters. Secondly, it is easy to find what you are looking for on the Internet. Even out-of-print books may be ordered on line. Finally, it is often cheaper to buy goods through the Internet, and you can tell the shop exactly what you want.
The main disadvantage of Internet shopping is that you cannot actually see the products you are buying or check their quality. Also, many people enjoy shopping in the city and miss the opportunity to talk to friends. Some people are worried about paying for goods using credit cards, so Internet companies are now finding ways to make on-line payment safe.
Internet shopping is sure to become more and more popular in the years ahead. It promises to change the way we buy all kinds of things—from tonight’s dinner to a new car.

In the passage, which of the following disadvantages of Internet shopping is not mentioned

A. customers cannot actually see the products they are buying
B. customers cannot check the product’s quantity they are buying
C. many people enjoy shopping in the city and miss the opportunity to talk to friends
D. some people are worried about paying for goods using credit cards