阅读下面一段话，要求用一句话概括其大意（用自己的语言，不抄袭原句），字数不超过20个单词。

Water had also appeared on other planets like Mars but, unlike the earth, it had disappeared later. It was not immediately obvious that water was to be fundamental to the development of life. What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acids into the oceans and seas. This produced a chain reaction, which made it possible for life to develop.