The completion of the Human Genome Project last year marked a milestone in medicine. The detailed mapping of the entire set of human genes was a decade-long project worked on by some of the best minds in biology. But in many ways it was only the beginning of the real medical challenge: understanding the million or so proteins that are the molecular workhorses of the human body. Genes are really just the programming code that tells cells how to synthesize proteins; almost all the biological action occurs among these large, complex molecules.

Select from the choices above to read the entire article.