Final answer:
Particles are tightly linked together in a definite shape in the solid state of matter. Solids have a defined volume and shape due to the fixed positions of their particles.The correct option is a.
Step-by-step explanation:
The state of matter where particles are tightly linked together in a definite shape is a solid. In a solid, the particles are in a fixed position relative to each other and are held close together by forces that give the solid a definite volume and shape. Unlike solids, liquids have a definite volume but no definite shape, and gases have particles that are far apart and move freely without a definite volume or shape.