What are the predominant organic acids present in softwoods such as pine and spruce?

I have a wood chemistry course in which we are asked to explain the hierarchy of the organic wood acids present in softwood species like pine or spruce. Could you please offer a few other possible organic acids that might be present in softwoods? I am only really interested in the predominant acids.

Hemoglobin as a Complexing Agent

Can we say that hemoglobin is a complexing agent? Discuss this issue, giving at least three reasons to substantiate your point of view.

Roles of Carbon and Silicon in Organic Chemistry

Carbon and silicon belong to the same group and are known to have similar properties. Do you think that silicon can replace the role that carbon plays in organic chemistry?