题目内容：

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Water had also appeared on other planets like Mars but,   1 the earth,it had  2  later. It was not immediately obvious  3 water was to be   4 to the development of life.    5 many scientists believe is that the continued   6   of water allowed the earth to dissolve  7 gases and acids into the oceans and seas. This produced a    8 reaction,  9  made  10  possible for life to develop.