Preserving food, less fighting for food, less roaming to hunt and gather. More stable sense of community. More children. Preserving food, less fighting for food, less roaming to hunt and gather. More stable sense of community. More children.
Contrast sensitivity is the ability of an imaging process to produce an image of objects or tissues in the body that have relatively small physical differences or inherent contrast. The contrast that is to be imaged is in the form of some specific physical characteristic.
The image point of the top of the object is the point where the two reflected rays intersect. If your were to draw a third pair of incident and reflected rays, then the third reflected ray would also pass through this point.