Top definition. Musk. Though technically the name for the secretion of the male musk deer, musk is most often used as the name for the scent of arousal in both men and women, as actual musk is used in perfumes and colognes. Generally causes arousal for both genders, as it is a secondary sex characteristic.
These photoreceptors are called the rods and cones. Rods are called rods because under the microscope, they are shaped like, of all things, a rod. Finally, those pesky scientists named a structure for what it actually looks like as opposed to someone's unpronounceable last name!
Rods and cones are photoreceptors that are located in the retina of the eye. Rods are responsible for vision at low light levels while cones are responsible for vision at higher light levels. Therefore, rods are very sensitive to light. Rods work well at night when light is low. Cones, however, are responsible for color vision and high visual spatial acuity. Therefore, rods cannot distinguish colors. With these differences, the correct answer is: A. Rods are very sensitive to light but do not distinguish colors.