## **Core Concept**
The process of putrefaction involves the breakdown of tissues by bacteria, typically those from the gastrointestinal tract. This process is influenced by factors such as the bacterial load, oxygen levels, and the tissue's composition.

## **Why the Correct Answer is Right**
The brain, being highly vascular and having a high water content, usually putrefies quickly. Similarly, the intestines, with their high bacterial load, also decompose rapidly. In contrast, the **lungs** are relatively resistant to putrefaction due to their lower bacterial load compared to the gastrointestinal tract and their aerated structure which might slow down the anaerobic bacterial growth. However, the organ known for being the last to putrefy is actually the **heart**, due to its dense structure and lower bacterial load.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Typically, organs with high bacterial loads or high water content putrefy quickly, not last.
- **Option B:** Similar to Option A, unless specified, most organs with significant blood supply decompose relatively fast.
- **Option C:** This could potentially be correct based on certain conditions, but generally, the heart is noted for its resistance.
- **Option D:** Not specified, but assuming it's an organ that usually decomposes quickly due to its nature.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the **heart** is often cited as one of the last organs to undergo putrefaction due to its dense structure. This fact can be crucial in forensic pathology for estimating post-mortem intervals.

## **Correct Answer:** D. **Heart**