(MS/HS) Created for high school anatomy and physiology students but available to all. Students brainstorm about the characteristics of plants, animals, protists, fungi, and bacteria that will allow them to tell the tissues/cells apart with a compound microscope. Then, students are given a mystery prepared slide with the label covered and relabeled letters A-E. They learn how to use the compound microscope to look closely at the slide, draw, and describe what they see, with the ultimate goal to match each letter to an organism. Students are encouraged to look at more than one mystery slide, depending on time limitation. Wrap up with processing student ideas and evidence, as well as the correct information and evidence thereof. Materials available: Student worksheet; Free note-taking worksheet.