1. In biology, cell theory is a scientific theory which describes the properties of cells. These cells are the basic unit of structure in all organisms and also the basic unit of reproduction.
- Multicellular organisms are organisms that consist of more than one cell, in contrast to single-celled organisms. Few unicellular species can be seen individually with the naked eye.
A unicellular organism, also known as a single-celled organism, is an organism that consists of only one cell, unlike a multicellular organism that consists of multiple cells.