Estimates of the cost of invasive species to the United States alone are in the tens of billions of dollars yearly. Annual federal expenditures on prevention and management of invasive species are estimated to exceed $1.3 billion.
Depending on what specific conditions are. Some of the color we see when we close our eyes is light that gets thru the eye lid. It usually has a red componenet to it because of the blood veins. Sone, especially right after closing our eyes is the various elements in our visual system settling down (rods, cones, ...).
The pupil is the black circle in the center of the iris, which is really an opening in the iris, and it lets light enter the eye. To see how this works, use a small flashlight to see how your eyes or a friend's eyes respond to changes in brightness.