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 layer of cells at the front of the retina contains the retinal ganglion cells, whose axons pass across the surface of the retina, collect in a bundle at the optic disc, and leave the eye to form the optic nerve.Each eye contains about 125 million rods and cones but only i million ganglion cells.ecause the rods and cones are at the back of the retina, the incoming light has to go through the other two layers in order to stimulate them. We do not fully understand why the retina develops in this curious backward fashion.