Hey PZ, that one is actually 19!!! <img src='http://www.melbournechat.org/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' />
ferroprotoporphyrins (20) or fluorodeoxyuridylate (20)
ferroprotoporphyrins (20) or fluorodeoxyuridylate (20)