Night visibility increases in paints having

Options

A. Foraminiferan ooze
B. Diatomaceous earth
C. Sporozoans
D. Noctiluca.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which substance increases night visibility in paints. We have four options to consider: formaldehyde, diatomaceous earth, sporozoans, and noctiluca.

2. **Analyzing the Options**:
- **Formaldehyde**: This is a chemical compound often used in various industrial applications, but it does not have properties that enhance visibility in paints.
- **Diatomaceous Earth**: This is a natural substance made from the fossilized remains of diatoms, which are single-celled algae. It has unique properties that can enhance the visibility of paints.
- **Sporozoans**: These are a group of parasitic protists and do not have any known applications in paint visibility.
- **Noctiluca**: This is a genus of marine dinoflagellates, known for bioluminescence, but it is not commonly used in paint formulations.

3. **Focusing on Diatomaceous Earth**: Diatomaceous earth is composed of silica, which comes from the hard shells of diatoms. When added to paint, it serves multiple purposes:
- It acts as a flattening agent, helping to create a smooth surface.
- The protruding parts of the diatom shells can diffract light, which enhances the shine and visibility of the painted surface, especially at night.

4. **Conclusion**: Based on the analysis, the correct answer is **diatomaceous earth**. It is the only option that contributes to increased night visibility in paints due to its light-diffracting properties.

**Final Answer**: Diatomaceous earth.

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