John wants to look at cells from the root of a young plant under the microscope. john cuts the tip off a root and puts it on a microscope slide. he adds two drops of iodine solution to stain the cells. he crushes the root by placing a plastic coverslip on top of it and pushing down on the coverslip gently with the eraser on his pencil.

a) suggest one reason why john uses a plastic coverslip instead of a glass one.

b) why does john need to stain the cells?