Domestic ferrets are just one breed, the colors are the type of ferrets. Within the genus Mustela, ferrets belong to the subgenus Putorius, from which there are only three extant species: M. putorius, the European polecat; M. eversmanni, the Siberian, or steppe polecat; and M. nigripes, the black-footed ferret.
Nearsightedness, also known as myopia, is a common type of refractive error where close objects appear clearly, but distant objects appear blurry. The cornea and lens bend (refract) incoming light rays so they focus in front of the retina.earsightedness, also known as myopia, is a common type of refractive error where close objects appear clearly, but distant objects appear blurry. The cornea and lens bend (refract) incoming light rays so they focus in front of the retina.
Most nearsightedness is caused by a natural change in the shape of the eyeball. Less often, nearsightedness may be caused by a change in the cornea or the lens. These problems cause light rays entering the eye to focus in front of the retina. Normally, light focuses directly on the retina.