to robin: I'm not a chemist, but your point about catalyzed reactions makes immediate, clear sense in dealing with sobrien60's objection. Thanks.
to mckay: I'm not entirely sure I understand your response about benzene. What I gather from robin's question is the idea that benzene may be the eventual trash heap of carbon, making it permanently inaccessible afterwards. While you seem to agree with this assessment about benzene, your point about its creation high in the atmosphere and presence on the surface doesn't discuss __quantities__ in both spheres relative to each other and relative to the larger situation as well and I think that is very important. Could you expand a little? Thanks.