Which statement describes why methylene blue stain is added to human cheek cells before viewing them under a light microscope?
To stain the nucleus and make cell structures more visible.
To kill the cells and stop respiration.
To prevent osmosis.
To stain starch.
40 exam-style questions on OCR GCSE Biology 1.1 Cell structures, covering 1.1.1 Viewing cells with light microscopes, 1.1.2 Sub-cellular structures and functions, and 1.1.3 Electron microscopy and resolution. Each one has a worked solution and a mark scheme showing where the marks go.