根据课文原文，填入所缺内容。
★ It was not immediately obvious that water was 1 the development of life.
★ This produced to be fundamental to 2a chain reaction , which made it possible for life to develop.
★ I earned my passage by working as an unpaid hand, which accounted for my appearance 3managed to catch sight of .
★ When they crossed the Rocky mountain, they 4 some mountain goats and even a grizzly and an eagle.
★ Many of them have a gift for 5 riding wild horses and can win thousands of dollars.
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