This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous Nervous System, Subject name: Physiology
In humans, the brain is considered to be "responsive": 
Select and explain. 
A. It has control centers for all motor actions and sensory inputs, B. Every cell of brain has got specific function, C. It is a closed system and so not influenced by changes occurring outside, D. Its functions are profoundly affected by changes in external environment
D: Its functions are profoundly affected by changes in external environment
Answer: D: Its functions are profoundly affected by changes in external environment 
Explanation: Ans. d. Its functions are profoundly affected by changes in external environmentIn humans, the brain is considered to be "responsive" as its functions are profoundly affected by changes in external environment.