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.
BiF14 HE LIGHT TOUCH Seeing in the light and in the dark T he human eye is remarkably sensi-tive. The first stage in the process of seeing is the absorption of light in cells called rods and cones, which lie in the retina, a thin sheet of tissue at the back of the eye. The retina records the image of the world around you somewhat like film does in a camera.