Answer:
The small, closely spaced particles that make up a mosaic are called "tesserae".
Step-by-step explanation:
Tesserae are small pieces of materials, such as glass, stone, ceramic, or other materials, that are used to create a mosaic artwork. They are typically square or rectangular in shape and are carefully arranged and placed to form a larger image or pattern. The tesserae are adhered to a surface, such as a wall, floor, or other substrate, using a binding material like mortar or adhesive. This technique allows for the creation of intricate and colorful mosaic designs by combining numerous small tesserae into a cohesive whole.