Which part of the brain acts as a relay centre?
A) Hypothalamus
B) Cerebrum
C) Cerebellum
D) Thalamus

Hint: Relay centre refers to the part that translated most of the stimuli to responses. Relying means taking some information and passing it to the main centre so that it can be decoded.

Complete Answer:
Our brain that looks so compact, is actually divided into three parts like forebrain, midbrain and hindbrain.
The thalamus is an important part of the forebrain. It is made up of specialised nerve cells that can receive the stimuli from various sense organs and process it so that it can be transferred further to the deeper part of the brain.

Our brain receives numerous stimuli at a given time. However, you must have noticed that when you give concentration to a certain task, like reading, you tend to even miss somebody calling your name. This is because of the thalamus that treats the major stimulus of reading as important and occupies the forebrain into decoding it to produce the response. Therefore, the thalamus is the relay centre of the human brain. Now think how difficult it will be for us to concentrate if the thalamus does not collect important messages while neglecting or surpassing others.

Cerebrum is concerned with regulating the responses to coordination of movement, temperature, touch, vision, hearing, judgment, reasoning, problem solving, emotions, and learning.

Cerebellum is majorly involved in coordination of learned movements and body posture.
Hypothalamus is made of secretory neurons that control the activity of endocrine glands via the control over the pituitary gland.

Note: Thalamus, hypothalamus and cerebrum are the parts of the forebrain while cerebellum is a part of hindbrain.