(a) Adaptation: Any receptor adapted by perceive a constant stimulus at a constant time. For example when you entering the room, you will notice a clock sticking but as you continue to work it reach a time to disappear.
(b) Spontaneous activity; Receptor has a property to sense a stimulus in absence of stimulus. For example some time you can hear sound likesone one call your name but not true, this is spontaneous activity of the receptor. This property has a biological important because it increase the sensitivity of a receptor
(c) Convergence and Summation; Receptor able to perceive a different stimulus and converge all of them at the same point. Summation is an accumulative or additive effect of all stimulus to be sent into the specific region.