1) Stimuli for various sensations are first received by the

brain

spinal cord

senses

environment

2)
An example of a contact external sense is.

hunger

common sense

taste

sight

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.