Which are characteristic properties of muscles?
All of these
Excitability is the ability to receive and respond to stimuli. Stimuli initiate nerve impulses which are interpreted by the brain and spinal cord and transmitted back to the muscles, causing them to respond.
Contractability is the ability to shorten and thicken or contract when a sufficient stimulus is received. This characteristic distinguishes muscle tissue from other types of tissue.
Extensibility is the ability to stretch or extend.