Which of the following is an example of cooperative behavior
a. a lion hunting zebra
b. two male peacocks fighting over a female peacock
c. a hyena stealing a a cheetahs kill
d. a blue jay calling to signal the presence of a hawk

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.