The gas responsible for puffing-up appearance of dough comes from:

1. Aerobic respiration

2. Fermentation

3. Photosynthesis

4. Photorespiration

Which of the following antibiotics was discovered first?
1. Streptomycin
2. Neomycin
3. Erythromycin
4. Penicillin

Acetic acid is produced by a:

1. Fungus

2. Bacterium

3.  Yeast

4.  Virus

The bioactive molecule cyclosporin A is used in:

1. Whooping cough

2. Diphtheria

3. Leprosy

4. Organ-transplant patients

The primary treatment of sewage involves:

1. Digestion

2. Decomposition

3. Sedimentation and filtration

4. None of these

The amount of oxygen required by the microbes in the decomposition of organic matter is called:

1. Chemical oxygen demand

2. Biochemical oxygen demand

3. Total oxygen demand

4. Dissolve oxygen

The mixture of gases released during anaerobic digestion of sludge is called:

1. Methane

2. Carbon dioxide

3. Biogas

4. Flammable gases

Biogas contains:

1.CO₂

2. H₂S

3. CH₄

4. All of these

The symbiotic association between fungi and roots of higher plants is called:

1. Lichen

2. Mycorrhiza

3. Biofertilizer

4. BOD

The organisms which are used to enrich the nutrient quality of the soil are called:

1. Mycorrhiza

2. Biofertilizers

3. Yeast

4. Methanogens