## Core Concept
Sodium borate, also known as borax, has specific applications in various medical and industrial processes. In the context of embalming fluids, additives are crucial for preserving the body, restoring a lifelike appearance, and preventing decay.

## Why the Correct Answer is Right
The correct answer, **D. as a fungicide and helps in preserving the eyes**, highlights the role of sodium borate in embalming fluids. Sodium borate has antiseptic properties, which help prevent the growth of fungi and bacteria. This is crucial in the preservation process, as it helps maintain the body's integrity for a longer period. Specifically, in preserving the eyes, sodium borate can help prevent desiccation and maintain their natural appearance.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is incorrect because while buffering agents are important in embalming solutions for maintaining pH, sodium borate's primary role is not as a buffering agent.
- **Option B:** This option is incorrect as there is no widely recognized role of sodium borate in significantly altering the osmotic balance in embalming fluids to prevent tissue swelling.
- **Option C:** This option is incorrect because, although antiseptics are crucial in embalming fluids, specifying sodium borate primarily as an antiseptic without acknowledging its role in preserving specific features like the eyes or its fungicidal properties might be misleading.

## Clinical Pearl / High-Yield Fact
A key point to remember is that additives in embalming fluids serve multiple purposes, including preservation, restoration of appearance, and prevention of decay. Sodium borate's multifunctional role, including its use as a fungicide and in preserving delicate features, underscores the complexity of embalming chemistry.

## Correct Answer: D. as a fungicide and helps in preserving the eyes