What do an eye, a telescope, and a microscope have in common?
a: they all reflect light to increase the size of an object.
b: they all contain lenses that act as photoreceptors to project an image.
c: they all contain a transparent part with at least one curved surface that refracts light.
d: they all refract light to make an object look closer.

As you sit in the library with your friend studying for your weekly quiz on the integumentary system, you come upon an article about the hazards of prolonged exposure to the sun's rays. your curious nature leads you to research the subject further. you're fascinated to learn that minimal exposure to the sun allows you skin to manufacture vitamin d, which is important to maintain homeostasis. you also read that although sunscreen can protect you from the ultraviolet (uv) rays of the sun, some medications can actually increase a person's sensitivity to the sunlight.