Read the text about the development of moving images and answer the questions in short.

Moving Images

Zoetropes and some other devices such as thaumatropes and praxinoscopes enabled people to watch moving images. These images looked real and alive and the reason for that is in our eyes. If our eyes see a light flash (a picture) every tenth of a second or less, they do not notice the gap between the pictures and we see movement.

The next important step in the development of the moving images was in 1872. Englishman Edward Muybridge, one of the pioneers of photography, met Leland Stanford, the former governor of California. At that time many people wondered if there was a moment when all four feet of a horse were in the air during a gallop, because the human eye could not follow the quick movements of the horse's legs when galloping. The two men decided to find the answer to this question scientifically. Muybridge set up 12 cameras along the edge of a racetrack. Then he attached string across the track. When the horse touched the string, it triggered the shutters on the cameras. This way, Muybridge got 12 images which he copied on a special disc. He played the images on a machine he had invented, the Zoopraxiscope - the first movie projector, and watched the horse galloping. While watching the horse gallop, he got the answer to his question: at some points all of the horse's hooves were up in the air.

This was the beginning of motion pictures that later developed into big business – film industry.