1.How Can You Classify Single-Celled Organisms?
Some of the oldest and most common organisms on Earth consist of only one cell. These single-celled, or unicellular, organisms display all of the characteristics of living things. You might think that all unicellular organisms are very similar, but this is not the case. These fascinating creatures are extremely diverse.

What characteristics do you think could be used to classify different kinds of single-celled organisms?