What term describes organisms that are composed of more than one cell?

The term that describes organisms composed of more than one cell is "multicellular." These organisms consist of numerous cells that work together to perform various functions, forming tissues and organs, which contribute to the overall complexity and specialization within the organism. Examples of multicellular organisms include humans, trees, and animals, all of which rely on the collaboration of their cells for growth, reproduction, and maintenance of life.

In contrast, the term "single-celled" refers to organisms made up of only one cell, like bacteria and certain kinds of protists. "Unicellular" is another term synonymous with single-celled. The term "bi-cellular" is not commonly used in biological classification and may lead to confusion, as it implies an organism of only two cells, which does not encompass the broader category of multicellular organisms.