3501: Acid rain is caused by pollution of environment by:
(a) Carbon dioxide and nitrogen
(b) Carbon monoxide and carbon dioxide
(c) Ozone and carbon dioxide
(d) Nitrous oxide and sulphur dioxide
3502: Disguised unemployment generally means
(a) large number of people remain unemployed
(b) alternative employment is not available
(c) marginal productivity of labour is zero
(d) productivity of workers is low
3503: Which Article of the Constitution provides that it shall be the endeavour of every State to provide adequate facility for instruction in the mother tongue at the primary stage of eduction ?
(a) Article 349
(b) Article 350
(c) Article 350-A
(d) Article 351
3504: The bats can fly in the dark because:
(a) They have a better vision in the dark
(b) The light startles them
(c) They produce ultrasonics
(d) None of the above
3505: Which of the following statements about Mohammad-bin-Tughlaq is correct?
(a) He introduced paper currency
(b) He introduced the postal system
(c) He was the ablest man among the crowned heads of the medieval age
(d) None of the above