**Question:** A reflex which never reappears is –

A. Babinski reflex
B. Achilles tendon reflex
C. Gastric reflex
D. Schirmer's reflex

**Core Concept:**

The question refers to reflexes, which are rapid, involuntary responses elicited by specific stimuli in the nervous system. Reflexes are essential for survival as they enable quick reactions, such as the withdrawal reflex in response to pain or the blink reflex in response to bright light. In this context, we are discussing reflexes that are specific to the human body and do not reappear after being extinguished.

**Why the Correct Answer is Right:**

The correct answer, D. Schirmer's reflex, is an example of a reflex that never reappears once extinguished. Schirmer's reflex is a defensive reflex involving the lacrimal gland and the cornea. It occurs when the cornea is stimulated, leading to the release of tears to protect the eye from potential injury or infection. The reflex is specific to the eye and is extinguished when the eye is closed or the cornea is covered.

**Why Each Wrong Option is Incorrect:**

A. Babinski reflex (also known as the Babinski sign) is a neurological reflex that occurs in response to a digital digit being applied to the sole of the foot and is a clinical sign in neurological examination. Although it may be seen in certain neurological conditions, it is not a reflex that never reappears after being extinguished.

B. Achilles tendon reflex is a common reflex seen in the lower limb, occurring when the Achilles tendon is stimulated. It is a clinical sign used in neurological examination and is not a reflex that never reappears after being extinguished.

C. Gastric reflex is related to the gastrointestinal system and is not a reflex that is being discussed in this question. It is involved in the coordination of the digestive process and does not pertain to reflexes that never reappear after being extinguished.

**Core Concept:**

Reflexes are essential components of the human nervous system, enabling quick and specific responses to protect the body from potential harm or maintain homeostasis. Reflexes are crucial in facilitating adaptive responses to external stimuli.

**Why Each Wrong Option is Incorrect:**

A. Babinski reflex is a neurological sign, not a reflex that never reappears after being extinguished. Testing the Babinski reflex involves stimulating the sole of the foot and observing the resulting plantar flexion of the great toe. Although this reflex may be seen in neurological conditions, it is not an example of a reflex that remains extinguished after being abolished.

B. Achilles tendon reflex is a common reflex observed in the lower limb, occurring when the Achilles tendon is stimulated. It is a clinical sign used in neurological examination and does not represent a reflex that remains extinguished after being abolished.

C. Gastric reflex is related to the gastrointestinal system and is not a reflex that is being discussed in this question. Reflexes pertinent to the gastrointestinal system are not related to reflexes that remain extinguished after being abol