The rods are narrower than the cones and distributed differently across the retina, but the chemical process in each that supports phototransduction is similar. A third class of mammalian photoreceptor cell was discovered during the 1990s: the photosensitive ganglion cells.
Answer Wiki. It depends on a lot of things. CA is used for the national internet domain and as the abbreviation for the country in most database programs. CDN is used as Canada's code for automobiles - if a Canadian vehicle is driven in Europe temporarily, it needs a CDN sticker to show the license plate is Canadian.
1. Use a period to show the end of a sentence. Hockey is a popular sport in Canada. The federal government is based in Ottawa. 2. Use a period after certain abbreviations. B.C. is the province located on the West Coast.