in this laboratory activity, you will be examining a section of an onion root tip under a compound light microscope. These slides were prepared by slicing the roots into thin sections, mounting them on glass microscope slides, staining so that the chromosomes are more visible, and then covering the specimen with a cover slip. You will classify each cell based on what phase it is in, and then count up the cells found in each phase. Use those numbers to predict how much time a dividing cell spends in each phase. what are the varibles