The substance that has a definite volume but no definite shape is a liquid.




Explanation:
A substance can exist in three states - solid, liquid, and gas. The state of a substance depends on the arrangement and movement of its particles.




Particles in Solids:
In a solid, the particles are closely packed together in a regular pattern. They have strong forces of attraction between them, which hold them in fixed positions. As a result, solids have a definite shape and volume. The particles in a solid can only vibrate in their positions and cannot move freely.




Particles in Liquids:
In a liquid, the particles are still close together but not as tightly packed as in a solid. The particles have weaker forces of attraction between them, allowing them to move more freely. They can slide past one another, but they still remain close together. Liquids do not have a definite shape, meaning they take the shape of the container they are poured into. However, they do have a definite volume because the particles are still close together and do not expand or compress easily.




Particles in Gases:
In a gas, the particles are far apart and move freely in all directions. They have very weak forces of attraction between them, allowing them to move independently. Gases do not have a definite shape or volume. They completely fill the container they are placed in and can expand or compress easily.




Conclusion:
Based on the given information, the substance that has a definite volume but no definite shape is a liquid. Liquids take the shape of the container they are poured into but still have a definite volume because their particles are close together and do not expand or compress easily.

I think it's liquid.