Which of these responses is not voluntarily controlled by the brain?

Step 1: Analyze the question We need the response that is not under voluntary (conscious) control of the brain. That means an involuntary action, usually a reflex.

Step 2: Explain the concept

• Voluntary actions are deliberately initiated by the cerebrum (the conscious part of the brain). Examples are walking, writing, talking and dancing.
• Involuntary actions (reflexes) happen automatically, without conscious thought. They are quick responses to a stimulus and travel along a reflex arc: stimulus → receptor → sensory neuron → spinal cord or brain stem → motor neuron → effector. Examples are blinking, coughing, sneezing, the knee-jerk and withdrawing your hand from a hot object.

Step 3: Evaluate each option

• A. Dancing: You decide to do it and control the movements. It is voluntary.
• B. Eating: You choose to pick up food, chew and swallow it. The start of eating is voluntary (although later swallowing in the oesophagus is automatic). It is voluntary overall.
• C. Sneezing: It is triggered by irritation of the nasal lining and is a reflex action coordinated by the brain stem (medulla). You cannot easily start it or stop it by will. It is involuntary.
• D. Writing: You consciously control it. It is voluntary.

Step 4: Answer The response that is not voluntarily controlled is sneezing, which is option C.

Exam tip: Remember the common reflex actions with the "BCS-K" idea: Blinking, Coughing, Sneezing, Knee-jerk. If you see any of these in the options, it is usually the answer to an "involuntary" question.