This page is designed to help us determine what elements are present in the atmospheres of different solar system bodies by comparing their atmosphere's spectra to the spectra of a simulated atmosphere that we can add different elements to.
Now that we have some idea of how adding molecules to the atmosphere effects the observed spectra, use your model atmosphere to compare to the spectra of Earth and Venus. What molecules do you think are present in these atmospheres? Does that fit with what you know about these planets?