Answer:
Plants and animals are called multicellular organisms because they are made up of more than one cell. Unlike unicellular organisms such as bacteria and protozoa, which consist of a single cell, plants and animals have specialized cells that are organized into tissues, organs, and organ systems. These cells work together to perform specific functions, such as obtaining nutrients, exchanging gases, and responding to the environment.
Multicellularity allows plants and animals to achieve a higher level of complexity and specialization than unicellular organisms, which can only perform limited functions. It also allows for greater efficiency in tasks such as movement, growth, and reproduction. The specialization of cells and tissues in multicellular organisms is one of the key features that distinguishes them from unicellular organisms, and it is essential for the proper functioning of these organisms as a whole.