Why is a layer of oil placed over yeast suspension in a methylene blue experiment?

  1. To feed the yeast
  2. To absorb CO₂
  3. To keep the temperature constant
  4. To prevent oxygen reoxidising the dye
Answer

D) To prevent oxygen reoxidising the dye

Oxygen would recolour the dye. AS & A Level Biology · Topic 12 Energy and Respiration · 12.2 Respiration

Biology MCQ · More A Level Biology: Energy and respiration MCQs · Practise