Shading is a common technique used by many visual artists to create the illusion of depth in a two-dimensional object. They do this by adding a denser amount of colours in one area to create darker points, to contrast with the lighter ones to display that there is a specific light source, allowing the art work to have various degrees of light and darks in a picture.
This is true, 1 axis turn = 24hrs/1day 1 rotation around the sun = about 365 days/1 year this motion causes the seasons and other natural happenings on earth
