Biology · PHOTOSYNTHESIS IN HIGHER PLANTS

Cornelius van Niel concluded that photosynthesis is essentially a light-dependent reaction wherein hydrogen from an oxidisable compound reduces \( \text{CO}_2 \). When purple and green sulphur bacteria carry out photosynthesis using \( \text{H}_2\text{S} \) as the hydrogen donor, the oxidation product formed is:

1. A
   Sulphur or sulphate
2. B
   Methane gas (\( \text{CH}_4 \))
3. C
   Water (\( \text{H}_2\text{O} \))
4. D
   Oxygen gas (\( \text{O}_2 \))