51: Three communicable diseases prevalent in developing countries caused by unsafe drinking water and bad sanitation are
(a) acute diarrhoea, cancer and gout
(b) malaria, acute diarrhoea and schistosomiasis
(c) onchocerciasis, leukaemia and arthritis
(d) rheumatism, malaria and AIDS
52: Mycorrhiza is a symbiotic association between
(a) Bacteria and roots of higher plants
(b) Algae and roofs of orchids
(c) Fungi and roots of higher plants
(d) Protozoa and roots of higher plants
53: Recently "oilzapper" was in the news, What is it?
(a) It is the latest technology to control the accidentally caused flames from oil wells
(b) It is an eco-friendly technology for the remediation of oily sludge and oil spills
(c) It is the latest technology developed for under-sea oil exploration
(d) It is a genetically engineered high biofuel-yielding maize variety
Explanation:
In the year 1997, TERI (The Energy and Resources Institute) initiated the research on crude oil and oil sludge degrading bacterial consortium. After seven year of research work, TERI developed the Oilzapper (crude oil and oily sludge degrading bacterial consortium). The oilzapper technology works effectively to clear the oil.
This bacterial consortium was developed by mixing five bacterial strains, which could degrade aliphatic, aromatic, asphaltene, and NSO (nitrogen, sulpur, and oxygen compounds0 fractions of crude oil and oily sludge.
54: Consider the following statements :
1. Caffeine, a constituent of tea and coffee is a diuretic.
2. Citric acid is used in soft drinks.
3. Ascorbic acid is essential for the formation of bones and teeth.
4. Citric acid is a good substitution for ascorbic acid in our nutrition.
Which of the statements given above are correct ?
(a) 1 and 2, only
(b) 1, 2 and 3, only
(c) 3 and 4 only
(d) 1, 2, 3 and 4
Explanation:
Caffeine, a constituent of tea and coffee is diuretic. caffeine increases diuretic action in the kidneys, increasing urinary volume and sodium extraction as a result of a decreasein the tubular re-absorption of sodium and water.
Citric acid, a weak organic acid is a good preservative and is also used to add an acidic taste to foods and soft drinks.
55: What is the order of magnitude of electric resistance of human body (dry)?
(a) 10X10 ohm
(b) 10X10X10X10 ohm
(c) 10x10x10x10x10x10 ohm
(d) 10x10x10x10x10x10x10x10 ohm
Explanation:
Human body is a good conductor because it contains 70% of water. Magnitude of electric resistance of human body (dry) is about one mega-ohm (10'6 ohm), when we measure body resistance by electronic multimeter.