Answer:
unicellular; multicellular
Step-by-step explanation:
The smallest and the most basic unit of life is the cell. Living organisms that are made of just one cell are said to be unicellular while those that are made up of multiple cells are said to be multicellular. Many unicellular organisms are some of the smallest living organisms to exist in nature. They cannot be seen with the ordinary eyes, except with the aid of microscopes.