Prepared microscope slides are generally sold in sets and are ready for viewing through the lens of a microscope. Children as well as researchers usually use such slides for educational purposes. Most prepared microscope slides consist of object glass, a covering glass, an object and optional liquid that can be added to examine the object further. Prepared microscope slide sets are available in variety of different subjects such as, single-celled creatures, invertebrates (insects), vertebrates (reptiles, birds and mammals), botanics and the human body.