Wall decorations made from small pieces of marble set in mortar were commonly seen in roman art. what is this type of artwork called?

This type of decoration is often called a mosaic. The definition of a mosaic is a picture or pattern produced by arranging together small colored pieces of hard material, such as stone, tile, or glass. Judging from your question, the correct answer would be A MOSAIC.

For example you could start a retail clothing store because you would need to have skills in business and you could start an photography business you would need to have skills in photography. hope this