我国科学家袁隆平培育出产量很高的杂交水稻品种，主要是利用了（

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问题选择题

我国科学家袁隆平培育出产量很高的杂交水稻品种，主要是利用了（　　）

A．生物基因的多样性

B．生物数量的多样性

C．生物种类的多样性

D．生态系统的多样性

答案

生物多样性通常有三个层次的含义，即生物种类的多样性、基因的多样性和生态系统的多样性．基因的多样性是指物种的种内个体或种群间的基因变化，不同物种（水稻和小麦）之间基因组成差别很大，同种生物如野生水稻和普通水稻之间基因也有差别，每个物种都是一个独特的基因库．我国动物、植物和野生亲缘种的基因多样性十分丰富，为动植物的遗传育种提供了宝贵的遗传资源．如我国科学家袁隆平用野生水稻与普通水稻杂交，培育出了高产的杂交水稻，表明生物基因的多样性是培育农作物新品种的基因库．

故选：A

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The Snowdonia Center
The Snowdonia Center for young mountain climbers has a climbing lesson. The beginners’ costs are $57 for a week, including food and rooms. Equipment (设备) is included except walking shoes, which can be hired (租用) at a low cost.
You must be in good health and prepared to go through body exercise. This could be the beginning of a lifetime of mountain climbing adventure (冒险).

Holiday News
Vacations now and in the school holidays at a country hotel in Devon. This comfortable, friendly home-from-home hotel is near the beautiful quiet countryside, but just a drive away from the sea. The food is simple but good. Children and pets are welcome. Reduced prices are offered for low season.

The World Sea Trip of a Lifetime
Our World Sea Trip of 2014 will be unlike any holiday that you have ever had before. You just go to bed in one country and wake up in another on the ship. But if you stay at one hotel after another as you traveled before, you’ll have to pack and unpack all your things, wait and travel during the tour.
On the ship, you will be well taken care of. Every meal will be first-class and every cabin (房舱) will be like your home.
During the trip, you can rest on deck (甲板), enjoy yourself in the game rooms and in the evening dance to our musical team and watch our wonderful play
You will visit all the places most people only dream about---from Acapulco and Hawaii to Tokyo and Hong Kong.
For a few thousand dollars, all the things can be yours.

小题1:What can you do if you like to go on holidays with pets?

A．Choose the holiday in Devon.

B．Go to the Snowdonia Center.

C．Join the World Sea Trip of 2014.

D．Visit Acapulco and Hawaii.

小题2:In what way is the Snowdonia Center different from the other two holidays?

A．It provides chances for families to get together.