651: What would happen if phytoplankton of an ocean is completely destroyed for some reason?
1. The ocean as a carbon sink would be adversely affected.
2. The food chains in the ocean would be adversely affected.
3. The density of ocean water would drastically decrease.
Select the correct answer using the codes given below :
(a) 1 and 2 only
(b) 2 only
(c) 3 only
(d) 1, 2 and 3
652: Acid precipitation is now regarded as a serious problem in some European and Asian countries. Its major cause or source is
(a) discharge of acidic effluents onto neutral or slightly alkaline land where the acidic components precipitate
(b) emissions of sulphur oxides and nitrogen oxides from thermal power plants and burning of fossil fuels; these oxides dissolve in atmospheric water vapour and fall back on earth as acid rain
(c) natural carbon dioxide released during respiration of living organisms dissolves in water, forming carbonic acid which is the chief contributor to acidity in rain water
(d) chloro-fluoro-carbons readily react with various chemicals near the earth's surface, producing acidic intermediates which cause acid precipitation
653: Which one of the following statements is correct ?
Fiscal Responsibility and Budget Management Act (FRBMA) concerns
(a) fiscal deficit only
(b) revenue deficit only
(c) both fiscal deficit and revenue deficit
(d) neither fiscal deficit nor revenue deficit
654: Which of the following crops are most suitable for cultivation under scanty rainfall conditions?
1. Horse gram
2. Rice
3. Mustard
4. Wheat
Select the correct answer from the codes given below:
(a) 1 and 2
(b) 2 and 4
(c) 2 and 3
(d) 1 and 3
655: The given diagram shows the number of students who failed in an examination comprising papers in English, Hindi and Mathematics. The total number of students who took the test is 500. What is the percentage of students who failed in at least two subjects ?
(a) 6.8
(b) 7.8
(c) 34
(d) 39