Concept:Effectors respond to nerve impulses; muscles and glands are the effector organs.
Receptors detect stimuli rather than produce responses.
Explanation:Effectors bring about visible actions such as contraction or secretion.
Examples of effectors from the options are the tongue, because it is muscular, and the ear glands, because they are glands.
The skin is one of the sense organs; it contains sensory receptors for touch, pressure, temperature and pain.
In a reflex action, the skin plays the role of a receptor organ, detecting the stimulus and passing the impulse to the nervous system.
It does not bring about the response itself.
Therefore, the skin is the organ among the listed options that is not an effector organ.
Answer:B. Skin