Answering just a few would 1. what is the one entity that varies among the three different kinds of cone cells? what is the nature of this variation? 4.   what is the difference between medium wavelength (mws) sensitive and long wavelength (lws) sensitive receptors/opsins? medium/sws wavelength sensitive receptors only have dichromatic vision and receptors with lws/mws will be trichromatic. 5.   why does having three color receptors (a. k.a. opsins) lead to a more complex color perception than just two? because the colors that each receptor detect overlap and the color ability in those overlapping areas is increased. 6.   what is the relationship between the chromophore (retinal) and the opsin protein of a cone cell? an opsin protein is a transmembrane protein in a cone cell, when stimulated by a photon activates, a chromophore molecule embedded in the opsin. when the retinal chromophore is activated it changes shape from an 11-cis arrangement to an all-trans arrangement. 7. evolution question: primates with only two types of opsin protein typically have better low-light vision than those with three opsin proteins. this is because dichromat primates typically have more rod cells than dichromat primates. what are rod cells, how do they work, and under what circumstances could having a high proportion of rod cells be evolutionarily adaptive?