题干

将纯种的高茎和矮茎豌豆间行种植,另将纯种的高茎和矮茎玉米间行种植,自然状态下,隐性性状(两种植物均为矮茎)植株所结种子发育成的F1,其表现型的情况是(  )

A:豌豆和玉米均有高茎和矮茎个体

B:玉米均为矮茎个体,豌豆有高茎和矮茎个体

C:豌豆和玉米的性状分离比均是3:1

D:豌豆均为矮茎个体,玉米有高茎和矮茎个体

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D

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    Global Positioning System (GPS) is now a part of everyday driving in many countries. It is a space-based system that provides position and time information in all weather conditions. GPS can help people get to where they want to go.____When this happens, the driver is often to blame. Sometimes a GPS error is responsible. Most often, it is a combination of the two.

    ____Barry Brown, a GPS technologist, took an incident as an example. His friend once flew to an airport in the eastern United States. There he borrowed a GPS-equipped car to use. He wrongly plugged in the home address in the west. It wasn't until he was driving for thirty minutes that he realized it. Mr. Brown says this is a common human error. But he says, “One problem is that GPS has a very small screen and it can just tell you the next turn.____

    “The Normal and Natural Troubles of Driving with GPS” lists several areas where GPS can cause difficulties. They include maps that are outdated, incorrect or difficult to understand. ____GPS may fail due to these reasons and then lead to confusion for the drivers.

    Although GPS sometimes causes difficulties when people are driving, the most attractive point of this system is its 100% coverage on the planet. It is important for you to have to know what you are doing when you use GPS. You need to have the “ability” to be able to use GPS because it sometimes goes wrong.____

A. There are quite a few situations showing the problems of using GPS.

B. That means that it is not really telling you about going to the wrong place.

C. This space-based system is an important tool for civil and commercial users.

D. But sometimes it sends you to the wrong place or leaves you completely lost.

E. They also contain timing problems related to when GPS commands are given.

F. Advances in technology play an active role in modernizing GPS in many ways.

G. To make GPS well used, you need a good understanding of how drivers and GPS work.