WAEC Biology 2010 Theory — Question 6

Model answer

Aim: To demonstrate the conditions necessary for germination. Method: Four beakers are labelled A, B, C and D, each containing a piece of cotton wool with dry bean seeds placed on it. In A, the seeds and cotton wool are left dry (no water added). In B, the cotton wool is moistened with water, but the beaker is kept in a refrigerator (cold, to exclude warmth). In C, the cotton wool is moistened and the beaker is placed on top of dissolved water so the seeds are submerged (excluding oxygen). In D, the cotton wool is moistened, warmth is maintained, and air/oxygen is freely available. Observation: The seeds in beakers A, B and C do not germinate because water, warmth, or oxygen (respectively) is missing, while the seeds in beaker D, where all three conditions are met, do germinate. Conclusion: Water, warmth and oxygen are all necessary for germination; if any one of them is missing, germination will not occur.