Question

Methanogens do not produce:

• A. Oxygen
• B. Methane
• C. Hydrogen sulfide
• D. Carbon dioxide

Hint:

Methanogens are: \[ \boxed{\text{Anaerobic archaebacteria}} \] Major biogas components: \[ CH_4 \; (50\!-\!70%) \] \[ CO_2 \] They function in the absence of oxygen and therefore do not produce: \[ \boxed{O_2} \] A common NCERT-based CUET and NEET question.

Answer 1

The Correct Option is A

Step 1: Recall the nature of methanogens. Methanogens are anaerobic microorganisms that belong to the group of archaebacteria. They are commonly found in:
• Marshy areas
• Biogas plants
• Rumen of cattle

Step 2: Understand their metabolic products. During anaerobic decomposition of organic matter, methanogens produce gases such as: \[ \text{Methane }(CH_4) \] \[ \text{Carbon dioxide }(CO_2) \] and traces of gases including hydrogen sulfide may be present in biogas.

Step 3: Evaluate the options.
• Oxygen \(\rightarrow\) Not produced by methanogens \(\checkmark\)
• Methane \(\rightarrow\) Major product of methanogens \(\times\)
• Hydrogen sulfide \(\rightarrow\) May occur in biogas mixtures \(\times\)
• Carbon dioxide \(\rightarrow\) Produced during anaerobic digestion \(\times\) Therefore, \[ \boxed{\text{Oxygen}} \] is not produced by methanogens. Hence, the correct answer is: \[ \boxed{\text{(A)}} \]