Understanding Particle Intermixing
Particles of matter are always in motion, and this motion allows them to intermix with one another. The correct answer to the question is option 'C', which refers to the **spaces** between the particles.

Why Spaces Matter
- **Molecular Structure**: All matter is made up of particles, such as atoms and molecules. These particles are not tightly packed; rather, they exist in a specific arrangement that includes spaces or gaps between them.
- **Free Movement**: The existence of spaces allows particles to move freely. For example, in gases, the particles are far apart and move quickly, facilitating easy intermixing. In liquids, the particles are closer but still have enough space to slide past one another.

Intermixing Process
- **Diffusion**: Intermixing occurs through processes like diffusion, where particles move from areas of higher concentration to areas of lower concentration. This process relies heavily on the spaces available between particles, as they allow for the movement and mixing of different substances.
- **Temperature Effects**: Increasing temperature often leads to greater kinetic energy, causing particles to move faster and occupy more space. This further promotes intermixing, as particles can spread out and mix with others more effectively.

Conclusion
In summary, the ability of particles to intermix with one another is fundamentally influenced by the spaces present between them. Understanding this concept is crucial in fields like chemistry and physics, as it lays the groundwork for studying various phenomena related to matter.