2976: Consider the following:
1. Birds
2. Dust blowing
3. Rain
4. Wind blowing
Which of the above spread plant diseases?
(a) 1 and 3 only
(b) 3 and 4 only
(c) 1, 2 and 4 only
(d) 1, 2, 3 and 4
2977: Assertion (A):
A Chemical reaction becomes faster at higher temperatures.
Reason (R):
At higher temperatures, molecular motion becomes more rapid.
(a) Both A and R are individually true and R is the correct explanation of A
(b) Both A and R are individually true but R is NOT a correct explanation of A
(c) A is true but R is false
(d) A is fasle but R is true
2978: Examine the following statements regarding a set of balls :
I. All balls are black.
II. All balls are white.
III. Only some balls are black.
IV. No balls are black.
Assuming that the balls can only be black or white, which two statements given above can both be true, but cannot both be false ? Choose the correct answer from the codes given below :
Codes :
(a) I and IV
(b) I and III
(c) II and III
(d) III and IV
2979: 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
2980: Which one of the following movements has contributed to a split in the Indian National Congress resulting in the emergence of 'moderates' and 'extremists'?
(a) Swadeshi Movement
(b) Quit India Movement
(c) Non-Cooperation Movement
(d) Civil Disobedience Movement