将具有一对相对性状的纯种豌豆个体间行种植，另将具有一对相对性状的纯种玉米个体间行种植。具有隐性性状的一植株上所产生的F1是( )。
A．豌豆和玉米都有显性个体和隐性个体
B．豌豆都为隐性个体，玉米既有显性又有隐性个体
C．玉米都为隐性个体，豌豆既有显性又有隐性个体
D．豌豆和玉米的显性和隐性比例都是3:1
参考答案：B
解析： 豌豆是自花传粉植物，而且是闭花受粉，所以豌豆在自然状态下，能避免外来花粉的干扰。玉米有自花传粉，也有异花传粉。
What do we really mean by being open? Being open is a kind of invitation to others to come in, to speak and to share. It is important in letting others get to know how we think and feel. In this way we will be understood and accepted by others. If we aren’t open with others, we won’t fully believe in ourselves or others. Here are a few ways for you to be more open. First, make your outside behavior the same with your inside feelings and thoughts. Second, share how you really feel about something instead of just opinions. Third, try to change your questions into statements(陈述句) and talk in the first person so that people will understand you more easily. For example, you might say, “I feel happy that you’re here,” instead of, “Are you glad that you’re here?” Finally, try not to say, “I don’t know.” This usually means I don’t want to think about it any more. Remember also that it is not suitable to be open with everyone in every situation. You may want to be more open with close friends, but not with people you don’t know well, because you are not sure how someone else will use what they know about you. Besides, some people may not be used to too much openness. If we say everything we feel or think to them, they will feel very uncomfortable at times. In all, being open is a good way for us to get on well with other people, but we’d better keep the balance between being open and not being too open.
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