WAEC Biology 2021 Objective — Question 23
Question 23 of 50 from the West African Examinations Council (WAEC) Biology 2021 Objective paper, with the correct answer and a full explanation.
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23. The diagram below is an illustration of the growth of a plant in a water culture. After a few days, the solution turned green and the plant died. Use it to answer questions 23 and 24. What precaution should have been taken to prevent the solution from turning green?
- A. Use a non-green plant for the experiment
- B. Aerate the solution daily
- C. Cover the culture vessel with opaque paperCorrect
- D. Keep cotton wool around the seedling to make it dry
Explanation
The green colour indicates algal growth, which needs light. Covering the vessel with opaque material blocks light and prevents algae from growing.
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