Answer to Question 1
Organic molecules have been found in comets and some meteorites. The large amount of water on Earth implies it was impacted by many comets in the past. Thus, organic molecules would have been introduced onto the Earth. Also, interstellar molecular clouds contain many complex molecules, which may have rained down on Earth during its formation.
Answer to Question 2
Our life is based on chains of carbon atoms with DNA, RNA, and proteins formed out of amino acids and nucleotides. Life as we know it depends on liquid water as its medium. It's possible other atoms may also be suitable for life to be based on, which would be radically different from ours.
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A consensus tree of life
Life Expectancy in Developed Countries
Plant life cycle