The technology of biogas production from cow dung was developed in India largely due to the efforts of

The residue left after methane production from cattle dung is

1. burnt

2. buried in land fills

3. used as manure

4. used in civil construction

Methanogens do not produce

1. oxygen

2. methane

3. hydrogen sulphide

4. carbon dioxide

Match the items in column "A' and coloum 'B' and choose the correct answer 

The correct answer is