The autonomic nervous system consists of neurons that control the

1. Analyze the question The question asks which body activity or structure the autonomic nervous system (ANS) controls.

2. Explain the concept The nervous system has two main functional divisions for the body's effectors:

• Somatic nervous system: controls voluntary actions, such as moving your hands, tongue and limbs (skeletal muscles).
• Autonomic nervous system: controls involuntary actions, which happen automatically without conscious thought. These include heartbeat, breathing rate, digestion (peristalsis), pupil size, sweating and gland secretion.

The ANS has two parts that work in opposition:

• Sympathetic: "fight or flight" (increases heart rate).
• Parasympathetic: "rest and digest" (slows heart rate).

3. Step-by-step solution

• A. Voluntary muscles: these are controlled by the somatic system, so this is wrong.
• B. Heart beat: the heart is cardiac muscle, which is involuntary and regulated by the ANS, so this is correct.
• C. Tongue: the tongue moves voluntarily (speaking, eating) through skeletal muscle, so this is wrong.
• D. Hands: these are moved voluntarily, so this is wrong.

4. Answer The correct option is B. heart beat.

5. Exam tip Remember: Autonomic = Automatic. If you do not have to think about it (heartbeat, digestion, breathing rate), the ANS controls it. If you decide to do it (waving, talking, writing), it is the somatic system.