Match List-I with List-II.
| List-I (Term) | List-II (Description) |
| A. Methanogens | I. Indirect measure of the organic matter present in water |
| B. Fermentors | II. Mixture of gases containing predominantly methane |
| C. Biochemical oxygen demand (BOD) | III. Bacteria that grow anaerobically on cellulosic material and produce methane |
| D. Biogas | IV. Very large vessels in which microbes are grown on an industrial scale |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → A-III, B-IV, C-I, D-II
(A) Methanogens — this matches (III) Bacteria that grow anaerobically on cellulosic material and produce methane. Methanobacterium is a common example. They live in anaerobic sludge and in the rumen of cattle, so cattle dung is rich in them.
(B) Fermentors — this matches (IV) Very large vessels in which microbes are grown on an industrial scale. Beverages and antibiotics are made in them.
(C) Biochemical oxygen demand (BOD) — this matches (I) Indirect measure of the organic matter present in water. BOD is the oxygen that would be used if all the organic matter in a litre of water were oxidised by bacteria. More organic matter means a higher BOD.
(D) Biogas — this matches (II) Mixture of gases containing predominantly methane. It is made by microbial activity and is used as a fuel, mainly in rural areas.
NCERT Extract:
Microbes in Industrial Products – “… Production on an industrial scale, requires growing microbes in very large vessels called fermentors (Figure 8.4).”
Microbes in Sewage Treatment – “… The BOD test measures the rate of uptake of oxygen by micro-organisms in a sample of water and thus, indirectly, BOD is a measure of the organic matter present in the water.”
Microbes in Production of Biogas – “Biogas is a mixture of gases (containing predominantly methane) produced by the microbial activity and which may be used as fuel. … However, certain bacteria, which grow anaerobically on cellulosic material, produce large amount of methane along with CO2 and H2. These bacteria are collectively called methanogens, and one such common bacterium is Methanobacterium.”