questions on photosynthesis and respiration

[T&JWilson]

        I am a high school student and am doing a reseach paper.  If you
could please answer my questions, it would be very helpful.
    How essential is the carbon cycle to life?
    What are your veiws on photosynthesis?
    Is glucose the only "food" in respiration?
    Is the oxygen that photosynthesis produces pure?
        Thank you very much for your help.
                                    Brianna Wilson
        wilstjb at earthlink.net