What is an example of a unicellular organism?

Bacteria are a prime example of unicellular organisms, which means they consist of a single cell that performs all the necessary functions for life. Unicellular organisms like bacteria can carry out processes such as nutrient uptake, waste elimination, reproduction, and response to environmental changes all within that one cell. This characteristic allows them to thrive in diverse environments, from soil to extreme habitats.

In contrast, fungi, plants, and animals are multicellular organisms, meaning they are made up of many cells that work together, each with specialized functions. While they display remarkable complexity and organization, they do not fit the definition of unicellular organisms like bacteria do.