Which Statement Concerning Receptors Is Correct

Multiple Choice

Which statement concerning receptors is correct?

A) They may be either a specialized ending of an afferent neuron or a special cell closely associated with the peripheral ending of an afferent neuron.
B) They are present for every modality in the environment.
C) When stimulated, they bring about opening of K⁺ channels in the efferent neuron membrane
D) Mechanical receptors are sensitive to varying amounts of heat