下图表示最初生活在某个区域的物种,由于水的阻碍,已将该物种分离成两个独立的种群。

题型:选择题

问题:

下图表示最初生活在某个区域的物种,由于水的阻碍,已将该物种分离成两个独立的种群。如果甲种群生活的环境发生剧烈的变化,那么种群甲的进化速度将可能

[ ]

A.甲比乙慢

B.甲比乙快

C.与乙相同

D.不能确定

考点:种群基因频率的改变与生物进化
题型:选择题

阅读理解。

     How did ancient people tell time?

     ◇Natural ways of keeping time

      In ancient time, people had to use the sun and the moon to tell time. They got up when the sun came

up and worked in the fields until the sun went down.

     ◇Man-made things

      The sand clock is made of two glass balls joined in a narrow neck. The top ball was filled with sand.

The sand slowly moved through the neck into the bottom (底部) hall. People knew the time by watching

how much sand fell to the bottom ball. People also made the water clock. They made a small hole near the

bottom of a pot. When the water in the pot dripped (滴) out, marking (刻度) inside the pot showed how

much fame passed.

     ◇Body clocks in living things

      Animals' body clock

      Animals don't need clocks to know time. They have their body clocks. Birds know when to fly to

warmer places before winter. Some animals know when to keep more food for the winter. Some fish know

when it's time to move up the river and lay eggs.

     Plants' own chock

     Plants have their own clocks to keep time. Plants know when to open flowers or when to drop their

leaves.

     Body clock in human beings

     People also have their own body clocks. When we get used to our lives, our body clocks can be very

exact. It can tell us when it's time to wake up. It can also tell us when to eat or to go to sleep.

1. How could an ancient farmer know when to go back home from the field in the daytime?

A. By looking at the moon.

B. By the sand clock or the water clock.

C. By looking at the sun.

D. By feeling whether tired or not.

2. According to the passage, how can animals know time?

A. They use body clocks.

B. They ask other animals.

C. They use the sun and the moon.

D. They make something to tell time.

3. How many kinds of living things with body clocks are mentioned here?

A. Two.

B. Three.

C. Four.

D. Six.

4. In what way is the sand clock the same as the water clock in telling time?

A. Both of them have a neck.

B. Both of them have two glass balls.

C. Both of them can be used only once.

D. Both of them give the time by quantity (数量).

5. The passage is mainly about _______.

A. man-made clocks

B. nature's clocks

C. time and clock

D. how people keep time

题型:选择题

患者女性,26岁,有心悸、胸闷病史。心电图如图5-5所示,应诊断为()

A.右心室肥厚

B.后壁心肌梗死

C.下壁心肌梗死

D.下、后壁心肌梗死

E.WPW综合征

题型:选择题

高压回路上的工作,需要拆除全部或一部分接地线后始能进行工作者,工作人员必须征得_____或_____的许可,方可进行,工作完毕后应_____恢复。

题型:选择题

碘的主要功能是参与()的构成。

A.皮质激素

B.性激素

C.甲状腺素

D.肾上腺素

题型:选择题

展览会的客户包括以下()。

A.组展商

B.专业观众

C.普通观众

D.赞助商

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