Igcse Model Questions Vol1 2022 Biology Question 1

A student prepares a slide of an onion (Allium cepa) epidermal peel, stains it with iodine solution and examines the cells under a light microscope at 40× objective. The lengths and widths of ten intact cells are measured with an ocular micrometer as shown in the table below. | Cell | Length (µm) | Width (µm) | |------|-------------|------------| | 1 | 45 | 30 | | 2 | 48 | 32 | | 3 | 44 | 31 | | 4 | 46 | 29 | | 5 | 47 | 33 | | 6 | 45 | 30 | | 7 | 49 | 31 | | 8 | 46 | 32 | | 9 | 44 | 29 | |10 | 48 | 30 | The textbook gives an average area of a typical onion epidermal cell as 1500 µm².