## **Core Concept**
The question pertains to the anatomical development of organs and structures in newborns, specifically focusing on which ones are of adult size at birth. This involves understanding human embryology and postnatal growth patterns.

## **Why the Correct Answer is Right**
The correct answer, , refers to the fact that the **lungs** are not fully inflated and are not of adult size at birth. At birth, the lungs are partially inflated and continue to grow significantly after birth. In contrast, certain structures like the **eyes**, **external ear**, and **genitalia** are relatively developed and of adult proportions or close to it at birth.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Eyes are relatively of adult size at birth.
- **Option B:** The external ear is also of adult size at birth.
- **Option D:** Certain aspects of the genitalia are of adult size or proportions at birth.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that while many structures are developed at birth, the lungs are a critical exception, requiring significant inflation and growth postnatally. This is crucial for understanding neonatal adaptation to extrauterine life.

## **Correct Answer:** . lungs