The cubic kilometer is a metric unit of volume equal to 1,000,000,000 cubic meters. The symbol of the cubic kilometer is kmÂ³ . km3 = 1,000,000,000 m3 = 109 m3. To convert cubic kilometers to hmÂ³, damÂ³, mÂ³, dmÂ³, cmÂ³ and mmÂ³ , multiply by one followed by as many trios of zeros as there are places between the cubic kilometer and the other unit.
Rod photoreceptors are very sensitive to light and are responsible for night vision. These are the most abundant cell type in the human retina and are located closest to the back of the eye, near the retinal pigmented epithelium (RPE).
The retina is about the size of a postage stamp. It consists of a central area called the macula and a much larger peripheral area of the retina. The light receptor cells within the retina are of two types, called the rods and the cones. Rods allow us to see in conditions of reduced illumination.