There are nine different essential oils in RC Blend. They are listed below along with a brief description of each oil. 1  Eucalyptus globulus Essential Oil - is one of many eucalyptus essential oils.  Eucalyptus radiata Essential Oil (Black Peppermint Oil) or Black Peppermint Oil is one of many eucalyptus essential oils.
Biology: We have cones! it is a part of our eye (on the retina, in the fovea). Cone cells, or cones, are one of the two types of photoreceptor cells that are in the retina of the eye which are responsible for color vision as well as eye color sensitivity (WIKIPEDIA)
Rod cell. Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than the other type of visual photoreceptor, cone cells. Rods are concentrated at the outer edges of the retina and are used in peripheral vision. On average, there are approximately 90 million rod cells in the human retina. More sensitive than cone cells, rod cells are almost entirely responsible for night vision.