sentence: A distinction is made between retinal tetrachromacy ( having four pigments in cone cells in the retina , compared to three in trichromats ) and functional tetrachromacy ( having the ability to make enhanced color discriminations based on that retinal difference ) .
question: what was _ distinguished _ from something ?
answers: retinal tetrachromacy having four pigments in cone cells in the retina , compared to three in trichromats