**Core Concept**
Biomedical waste management is a critical aspect of infection control and public health. Yellow bags are designated for disposing of human anatomical waste, microbiology and biotechnology waste, animal waste, and soiled waste. However, certain types of waste are not suitable for disposal in yellow bags due to their hazardous nature.

**Why the Correct Answer is Right**
Reactive chemical wastes, such as those containing strong acids or bases, cannot be disposed of in yellow bags. This is because they pose a significant risk of chemical reactions and fires during incineration, which can lead to the release of toxic gases. Yellow bags are designed for incineration, and the addition of reactive chemicals can compromise the safety of the process. Reactive chemical wastes require specialized disposal methods, such as neutralization, stabilization, or chemical treatment, to prevent environmental contamination and ensure public safety.

**Why Each Wrong Option is Incorrect**
**Option B:** Radiographic wastes, such as X-ray films and cassettes, can be disposed of in yellow bags. They are typically incinerated, and the resulting ash is non-hazardous.
**Option C:** PVC (polyvinyl chloride) materials, such as medical devices and tubing, can also be disposed of in yellow bags. They are usually incinerated, and the resulting residues are non-toxic.
**Option D:** Human anatomical wastes, such as tissues and organs, are the primary contents of yellow bags. They are incinerated to prevent the spread of disease and to reduce the risk of infection.

**Clinical Pearl / High-Yield Fact**
The segregation and disposal of biomedical waste is a critical aspect of infection control and public health. It is essential to follow standard protocols for waste disposal, including the use of color-coded bags, to prevent environmental contamination and ensure public safety.

**✓ Correct Answer: A. Reactive chemical wastes**