The virtual assistant in iOS can do all kinds of stuff, of course. But here are the 16 things we think everyone should try at least once.
In most vertebrates and some molluscs, the eye works by allowing light to enter and project onto a light-sensitive panel of cells, known as the retina, at the rear of the eye. The cone cells (for colour) and the rod cells (for low-light contrasts) in the retina detect and convert light into neural signals for vision.
1 the retina The retina is the inner layer of the eye. 2  It contains the light receptors, the rods and cones (and thus serves as the film of the eye). 3  The retina also has many interneurons that process the signals arising in the rods and cones before passing them back to the brain. This not only reduces the amount of light entering the eye but also improves its image-forming ability (as does stopping down the iris diaphragm of a camera). 2  the retina The retina is the inner layer of the eye. 3  It contains the light receptors, the rods and cones (and thus serves as the film of the eye).