A student investigated the leaf anatomy of Nerium oleander, a xerophytic plant, to study its adaptation to dry environments. Using a light microscope, they took a photomicrograph of the lower epidermis. The printed photomicrograph has a width of 150 mm and a height of 100 mm. The magnification of the image is ×400\times 400×400. The student counted exactly 15 stomata in this field of view.
Which of the following is the correct stomatal density of this leaf?
0.40 stomata mm−20.40\text{ stomata mm}^{-2}0.40 stomata mm−2
160 stomata mm−2160\text{ stomata mm}^{-2}160 stomata mm−2
24.0 stomata mm−224.0\text{ stomata mm}^{-2}24.0 stomata mm−2
0.00625 stomata mm−20.00625\text{ stomata mm}^{-2}0.00625 stomata mm−2
34 exam-style questions on OCR A A Level Biology Exchange surfaces. Each one has a worked solution and a mark scheme showing where the marks go.