Question 1
The adjustable ring of circular and radial muscles that controls the amount of light entering the eye is the
◦ lens.
◦ cornea.
◦ pupil.
◦ iris.
◦ retina.
Question 2
The body's "natural opiates" used to reduce the ability to perceive pain are
◦ glucocorticoids.
◦ mineralocorticoids.
◦ endorphins and enkephalins.
◦ endorphins only.
◦ enkephalins only.