Related by context. Frequent words. (Click for all words.) 62 rhodopsin 60 waxy substance 59 papillae 58 photoreceptor 58 sclera 58 ganglion cells 58 medulla 57 pinkish red 57 porphyrins 57 iridescence 57 fluoresces 57 membranous 56 mottling 56 photoreceptors 56 photoreceptor cells 56 olfactory receptors 55 sooty mold 55 striations 55 fluorescent molecules 55 speckles 55 chromophore 55 pigment 55 fundus 55 sebaceous glands 55 retinal pigment epithelium 54 protuberances 54 staghorn 54 snail shell 54 exudate 54 stippled 54 vacuoles 54 sensory organs 54 cambium 54 diffracted 54 cartilaginous 54 iridescent blue 54 greenish brown 53 tannic acid 53 coloration 53 neural tissue 53 receptor molecule 53 morphology 53 otolith 53 fruiting bodies 53 fluorescent probes 53 ciliary 53 Ultraviolet light 53 mesoderm 53 electrophoretic 53 retinal ganglion cells 53 whorl 53 serrations 53 fluorescing 53 whorls 52 chloroplasts 52 morphogenesis 52 collagen fibers 52 primary visual cortex 52 melanosomes 52 bird beak 52 brownish red 52 xylem 52 ganglion 52 purplish red 52 lamina 52 setae 52 paramagnetic 52 brownish gray 52 photocatalyst 52 fluorescent dye 52 plasmon 52 pineal gland 52 epithelia 52 chromophores 52 fluoresce 52 reddish pink 52 threadlike 52 pigmentation 51 fluorescently labeled 51 silvery gray 51 anemone 51 protein fragment 51 photonic crystal 51 scalloped edges 51 magnifying lens 51 grayish brown 51 luminescent 51 phosphorescence 51 fluorescence 51 chitin 51 dye molecules 51 flatworms 51 inchworm 51 outermost layer 51 epithelial cell 51 odorant receptors 51 reddish color 51 finely textured 51 female reproductive tract 51 photosensitive 51 AMPA receptors