Which term refers to the tiny pieces that make up a mosaic?

Tessera:refers to the tiny pieces that make up a mosaic

Explanation:

Mosaic is an image or art which is made from the collection of the small pieces of stone, colored glass or other types of material, Most of the Mosaics are made from small pieces of glass or stone of different types of colors called as tessera. It is used for the interior decoration work.

Tessera is the term refers to the individual tiny pieces that are used to make a mosaic, it is also called as abaculus.

The tiny pieces are made of cube shaped small tile, tesserae are mostly made of glass, clay, stone, ceramic and mirror.

In 200 BCE tesserae was used in the Greek Hellenistic Mosaics.

Thus  Tessera :refers to the tiny pieces that make up a mosaic

the correct option is option d