下列因素中，利于使地球上形成具有适合生物生存的温度条件的是
A．地球的体积和质量适中
B．太阳日的时间不太长
C．正午太阳高度的季节变化
D．昼夜长短的季节变化
答案：B
题目分析：一个太阳日的时间为24小时，日照时间不太长利于使地球上形成具有适合生物生存的温度条件。
点评：本题难度较小，可用排除法。地球的体积和质量适中形成包围地球的大气层；正午太阳高度的季节变化与昼夜长短的季节变化造成地球表面的季节更替。
图解地球上存在生命的条件：
阅读下面短文, 掌握其大意, 然后从1—10各题所给的A、B、C和D项中, 选出最佳选项, 并在答题卡上将该项涂黑。 Philo Farnsworth, the inventor of one of the country’s greatest machines was actually born in a log cabin, 1 to high school on horse back and without 2 of university degree（indeed, at age 14）, thought of the idea of electronic television. In 1906 Farnsworth was born in a community near Beaver City, Utah, 3 by his grandfather. 4 he was 12, his family moved to a ranch （大牧场）in Rigby, Idaho, which was four miles from, the nearest high school, 5 necessitating（使成为必要）his daily horseback rides. Because he was interested in the electron and electricity, he persuaded his chemistry teacher, Justin Tolman, to give him 6 instruction and to allow him to listen to a senior course. The death of his father forced him to leave at the end of his second year, but, as it 7 , at no great intellectual cost. There were, at the time, no more than a handful of men 8 the planet who could have understood Farnsworth’s idea for building an electronic television system, and it’s 9 that any of them were at this local community. One such man was Vladimir Zworykin who had moved to the US from Russia with a Ph. D in electrical engineering. He went to work for Westinghouse with a dream of building an all-electronic television system. But he wasn’t 10 to do so.
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