<span>Refraction happens when there</span> is a bending of path of a light wave as it
passes across the boundary separating two media and the degree of bending is
determined in part by the total change in velocity as the light<span> passes from one medium to the other. In
addition, the change in speed experienced by a
wave when it changes medium can result in a number of beautiful optical effects. </span>
Collagen supported cells :)
I think the answer is Endospore. I'm sorry if I'm wrong...