Which type of organism is characterized as being composed of many cells?

The correct choice is multicellular because organisms that are multicellular consist of multiple cells working together. This cellular organization allows for specialization, where different cells can perform specific functions, contributing to the overall complexity and efficiency of the organism. Multicellular organisms include a wide range of life forms, such as plants, animals, and fungi, all of which rely on the cooperation of various cell types to sustain life processes.

In contrast, multinucleate organisms contain many nuclei within a single cell, which does not fit the definition of being composed of many individual cells. Motile refers to the ability of organisms to move independently, which is not inherently linked to the number of cells they possess. Monocellular organisms, such as bacteria and some protists, are composed of a single cell, making them the opposite of multicellular organisms.