Concept:
The cerebellum is an important part of the hindbrain responsible for coordination of voluntary muscular activities and maintenance of body posture and equilibrium.
Step 1: Functions of cerebellum.
The cerebellum performs several essential functions:
• Maintenance of posture
• Regulation of muscle tone
• Coordination of voluntary movements
• Maintenance of balance and equilibrium
Step 2: Effect of cerebellar damage.
When the cerebellum is damaged, muscular coordination becomes defective.
The person experiences difficulty in:
• Walking properly
• Maintaining posture
• Performing coordinated movements
• Maintaining body balance
Step 3: Eliminate incorrect options.
Coma is usually associated with severe damage to the reticular activating system.
Excessive hunger is related to hypothalamic functions.
Loss of speech generally results from damage to speech centers of the cerebrum.
Thus these options are incorrect.
Step 4: Final conclusion.
Damage to the cerebellum causes:
\[
\boxed{\text{Loss of balance}}
\]
Hence option (D) is correct.