Question

Match List-I with List-II
List-I (Organ)
(A). External ear
(B). Middle ear
(C). Inner ear
(D). Retina
List-II (Embryonic part from which it develops)
(I). Endoderm of the $1^{st}$ pharyngeal pouch
(II). Ectoderm of $1^{st}$ branchial groove
(III). Neuroectoderm
(IV). Ectoderm lateral to developing hind brain
Choose the correct answer:}

• (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
• (A) - (II), (B) - (I), (C) - (III), (D) - (IV)
• (A) - (II), (B) - (I), (C) - (IV), (D) - (III)
• (A) - (III), (B) - (IV), (C) - (I), (D) - (II)

Hint:

Always associate the External ear with the outer groove (Ectoderm/Groove), the Middle ear with the inner pocket (Endoderm/Pouch), and the Retina directly with the brain (Neuroectoderm).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The organs of special senses (hearing, balance, and vision) arise from highly coordinated embryological interactions involving different germ layers (ectoderm, endoderm, and neuroectoderm).

Step 2: Detailed Explanation:
Let us match the organs with their embryological origins:
- (A) External ear: The external acoustic meatus develops from the invagination of the ectoderm of the first pharyngeal (branchial) groove (II).
- (B) Middle ear: The tympanic cavity and the auditory (Eustachian) tube develop from the expansion of the endoderm of the first pharyngeal pouch (I).
- (C) Inner ear: This begins as a thickening of the surface ectoderm lateral to the developing hindbrain, known as the otic placode. This placode invaginates to form the otic vesicle (otocyst), which gives rise to the membranous labyrinth. Thus, it develops from ectoderm lateral to the developing hindbrain (IV).
- (D) Retina: The retina is an outgrowth of the diencephalon of the brain. The optic vesicle invaginates to form the double-walled optic cup, which is composed entirely of neuroectoderm (III).
Combining these: (A)-(II), (B)-(I), (C)-(IV), (D)-(III).

Step 3: Final Answer:
This corresponds to option (C).