Explanation:

Introduction:
Matter is anything that has mass and occupies space. It exists in three main states: solid, liquid, and gas. These states of matter depend on the arrangement and movement of particles.

Liquid state:
The liquid state of matter is characterized by particles that are close together but not arranged in a fixed pattern like in solids. In liquids, the particles have more freedom to move around compared to solids. This results in a lack of a fixed shape, as liquids take the shape of the container they are in. However, liquids have a definite volume because the particles are still closely packed together.

Gasous state:
On the other hand, the gaseous state of matter is characterized by particles that are far apart and move freely. Gases do not have a fixed shape and will expand to fill the entire volume of the container they are in. They can be compressed easily because of the large spaces between particles.

Explanation of the correct answer:
The correct answer to the given question is option B, the liquid state. In the liquid state, matter has no fixed shape but still has a definite volume. This is because the particles in a liquid are close together and can move around freely, allowing the liquid to take the shape of its container. However, the particles remain close enough to maintain a definite volume.

Other options:
- Option A, the gaseous state, is incorrect because gases have no fixed shape and no definite volume. They can expand or contract based on the container they are in.
- Option C, the solid state, is incorrect because solids have a fixed shape and a definite volume. The particles in a solid are closely packed together in a regular pattern, giving them a specific shape that does not change easily.

Conclusion:
In conclusion, the state of matter that has no fixed shape but has a definite volume is the liquid state. Liquids can flow and take the shape of their container, but they still maintain a constant volume due to the close arrangement of particles.

Liquid state.