Eye color Light and light-mixed eyes (16–12 in Martin scale) Pure light (16–15 in Martin scale) Light-mixed (14–12 in Martin scale) Mixed eyes (11–7 in Martin scale) Mixture of light eyes (blue, gray or green) with brown when light and brown appearance is at the same level. Dark and dark-mixed eyes (6–1 in Martin scale) Amber eyes are of a solid color and have a strong yellowish/golden and russet/coppery tint. This may be due to the deposition of the yellow pigment called lipochrome in the iris (which is also found in green eyes). Amber eyes should not be confused with hazel eyes;
Returns to scale Returns to scale In economics, returns to scale and economies of scale are related but different concepts that describe what happens as the scale of production increases in the long run, when all input levels including physical capital usage are variable (chosen by the firm). The concept of returns to scale arises in the context of a firm's production function. It explains the behavior of the rate of increase in output (production) relative to the associated increase in the inputs (the factors of production) in the long run. In the long run all factors of production are variable and subject