Hydrogencarbonate indicator turns purple near a plant in bright light because

  1. respiration adds carbon dioxide
  2. oxygen turns it purple
  3. light turns it purple
  4. photosynthesis removes carbon dioxide
Answer

D) photosynthesis removes carbon dioxide

Low CO₂ makes the indicator purple. O Level Biology · Topic 6 Plant Nutrition · 6.1 Photosynthesis

Biology MCQ · More O Level Biology: Plant Nutrition MCQs · Practise