What do lenses do?
a: reflect light
b: refract light
c: concave mirror
d: interfere with light

A convex lens makes light rays converge (come together) at the focal point or focus. The distance from the center of the lens to the focal point is the focal length of the lens. Convex lenses are used in things like telescopes and binoculars to bring distant light rays to a focus in your eyes.

B:refract light  when a focused beam of light hits the lens it splits apart into smaller beams 

On the galapagos islands charles studied finches