## **Core Concept**
The question describes a male infant presenting with abdominal distension shortly after birth and decreased passage of meconium, which are classic symptoms suggestive of **Hirschsprung's disease**. This condition is characterized by the congenital absence of ganglion cells in the distal bowel, leading to a functional obstruction. The diagnosis is often confirmed by a rectal biopsy.

## **Why the Correct Answer is Right**
The rectal biopsy in Hirschsprung's disease is expected to show an **absence of ganglion cells** in the submucosal and myenteric plexuses of the affected segment of the bowel. This absence leads to a failure of the affected segment to relax and pass stool, causing the obstruction. The biopsy is a critical diagnostic tool, and the histological findings are key to confirming the diagnosis.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not specify the absence of ganglion cells, which is the hallmark of Hirschsprung's disease.
- **Option B:** This option is incorrect as it suggests an increase or presence of ganglion cells, which would not be indicative of Hirschsprung's disease.
- **Option C:** Without specific details, it's hard to directly refute, but generally, any option not indicating the absence of ganglion cells would not align with the diagnosis of Hirschsprung's disease.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that **Hirschsprung's disease** often presents with abdominal distension and failure to pass meconium within the first 48 hours of life. A rectal biopsy is diagnostic, showing aganglionosis. Remember, the condition predominantly affects males and can be associated with other genetic syndromes.

## **Correct Answer:** . Absence of ganglion cells.