Are single celled organisms very simple creatures?

Answer 1

No they are not simple creatures because they have to do everything themselves such as: make their own food and storing their own food, ect.

Answer 2

Single-celled organisms can vary widely in complexity. Some, like bacteria, are relatively simple in structure and function. Others, like protists, can be much more complex and exhibit various specialized organelles and behaviors. However, all single-celled organisms are considered relatively simple compared to multicellular organisms.