Microorganisms are used during which stage of the purification of the sewage water?

(1) Primary treatment

(2) Secondary treatment

(3) None of the above

(4) Both (1) and (2)

The maximum concentration of alcohol in beverages that are naturally fermented is:
1. 5 - 10%
2. 10 - 15%
3. 20 - 25%
4. 45 - 50%

Big holes in Swiss cheese are made by a:

(1) a machine

(2) a bacterium that produces methane gas

(3) a bacterium producing a large amount of carbon dioxide

(4) a fungus that releases a lot of gases during its metabolic activites.

The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is:

(1) Vitamin C

(2) Vitamin D

(3) Vitamin B12

(4) Vitamin E

Which one of the following alcoholic drinks is produced without distillation?

(1) Wine

(2) Whisky

(3) Rum

(4) Brandy

Match the following list of bacteria and their commercially important products:

Choose the correct match:

(1) (i) - b, (ii) - c, (iii) - d, (iv) - a

(2) (i) - b, (ii) - d, (iii) - c, (iv) - a

(3) (i) - d, (ii) - c, (iii) - b, (iv) - a

(4) (i) - d, (ii) - a, (iii) - c, (iv) - b

The residue left after methane production from cattle dung is:

1. burnt

2. burried in land fills

3. used as manure

4. used in civil construction

BOD of waste water is estimated by measuring the amount of:

(1) total inorganic matter

(2) biodegradable organic matter

(3) oxygen evolution

(4) oxygen consumption.

The free-living fungus Trichoderma can be used for:

1. killing insects

2. biological control of plant diseases

3. controlling butterfly caterpillars

4. producing antibiotics

The primary treatment of waste water involved the removal of:

(1) dissolved impurities

(2) stable substances

(3) toxic substances

(4) harmful bacteria.