## **Core Concept**
The clinical presentation described for the newborn, including a bloated abdomen shortly after birth and passing less meconium, is highly suggestive of **Hirschsprung's disease**. This condition is characterized by the 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 correct answer, which is not explicitly provided, is likely related to the histopathological features of Hirschsprung's disease. In Hirschsprung's disease, the hallmark finding on rectal biopsy is the **absence of ganglion cells** in the submucosal and myenteric plexuses of the affected bowel segment. This absence leads to a failure of the affected segment to relax and pass stool, causing the obstruction. The biopsy is considered the gold standard for diagnosing Hirschsprung's disease.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Without specific details on what each option represents, we can infer that any option not showing an absence of ganglion cells would be incorrect for the diagnosis of Hirschsprung's disease.
- **Option B:** Similarly, if this option does not accurately depict the absence of ganglion cells, it would not support the diagnosis.
- **Option C:** This option might represent another histological feature not specific to Hirschsprung's disease or a normal finding.
- **Option D:** Assuming this is not the correct representation of the absence of ganglion cells, it would be incorrect.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl for Hirschsprung's disease is that it often presents with **constipation or obstipation** (failure to pass meconium within the first 48 hours of life) and abdominal distension. A rectal biopsy showing an absence of ganglion cells confirms the diagnosis. A useful mnemonic is not directly applicable here, but remembering that the condition involves an **absence of ganglion cells** is crucial.

## **Correct Answer:** . **aganglionosis**