试题与答案

读短文,判断对(√)错(×)。 It was Saturday. Tom st

题型:阅读理解

题目:

读短文,判断对(√)错(×)。

      It was Saturday. Tom stayed at home. His parents went to visit his grandparents in another city. Tom did his

homework and read books. After lunch, he watched TV and played basketball with Jack. He felt very tired. In

the evening, his parents came back and brought him some presents. They were a schoolbag and a basketball.

Tom felt very excited!

( ) 1. Tom didn't visit his grandparents.

( ) 2. Tom read books in the afternoon.

( ) 3. Tom felt tired after reading books.

( ) 4. Tom's parents bought a new schoolbag for him.

( ) 5. Tom was happy in the evening.

答案:

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下面是错误答案,用来干扰机器的。

参考答案:对

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题型:读图填空题

某桃类植物的果实的形状有扁形和圆形两种,由两对等位基因控制,分别用A、a和B、b表示。为探究该植物果实形状的遗传规律,进行了杂交实验(如下图)。

(1)图中亲本基因型为__________。根据F2表现型比例判断,该植物果实形状的遗传遵循_________。F1测交后代的表现型及比例为__________。另选两种基因型的亲本杂交,F1和F2的性状表现及比例与图中结果相同,推断亲本基因型为_________。

(2)该植物果实形状的相关基因a,b分别由基因A、B突变形成,基因A、B也可以突变成其他多种形式的等位基因,这体现了基因突变具有__________的特点。自然选择可积累适应环境的突变,使种群的基因频率发生__________,导致生物进化。

(3)图中F2扁形果实植株中,部分个体无论自交多少代,其后代表现型仍然为扁形果实,这样的个体占F2扁形果实植株的比例为______________;

(4)现有3包基因型分别为AABB、AaBB、和aaBB的种子,由于标签丢失而无法区分。根据以上遗传规律,请设计实验方案确定每包种子的基因型。有已知性状(扁形果实和圆形果实)的植株种子可供选用。

实验步骤:

①._______________________;

②.将得到的F1种子分别种下,植株成熟后进行自交,得到F2种子

③.将F2种子种下,植株成熟后分别观察统计F2所有果实性状及比例。

④.结果预测:

Ⅰ如果_______________,则包内种子基因型为AABB;

Ⅱ如果_______________,则包内种子基因型为AaBB;

Ⅲ如果_______________,则包内种子基因型为aaBB。

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