Which of the following statements best describes the composition of rocks?

a. rocks always consist of a single type of mineral.
b. rocks can only be made up of a combination of three types of mineral.
c. rocks are made up of one or more types of mineral.
d. rocks are made up of at least three different types of mineral.

Which theory was contradicted by experiments with the photoelectric effect? light spreads out after it passes through a small opening. as soon as light strikes metal, electrons will be ejected. visible light, regardless of color, will cause the ejection of electrons when striking metal. the kinetic energy of ejected electrons depends on the frequency of light that strikes the metal.