Concept: This question tests your knowledge of the functions of different parts of the brain, specifically focusing on the critical roles of the hypothalamus.

Why (D) is correct: The hypothalamus is a vital part of the brain located below the thalamus. One of its primary functions is to act as the body's main thermostat, regulating various homeostatic processes, including body temperature, hunger, thirst, sleep-wake cycles, and endocrine functions. Injury to this region would severely impair the body's ability to maintain a stable internal temperature.

Why other options are wrong:

• (A) short - term memory: Short-term memory is primarily associated with the hippocampus and other limbic system structures, not the hypothalamus.
• (B) co-ordination during locomotion: Coordination of movement and locomotion is mainly controlled by the cerebellum.
• (C) executive functions, such as decision making: Executive functions like decision-making, planning, and problem-solving are primarily handled by the prefrontal cortex.

NEET Tip: Remember that the hypothalamus is the 'master regulator' for many homeostatic functions. Think of it as the control center for your body's internal environment.

Correct Answer: (D)