475. The most common substance responsible for the pollution is
(a) Sulphur dioxide
(b) Carbon dioxide
(c) Smoke
(d) Carbon monoxide
476. If a large number of people are enclosed in a room, then
(a) Oxygen increases and carbon dioxide decreases
(b) Oxygen decreases and carbon dioxide increases
(c) Both oxygen and carbon dioxide decrease
(d) Both oxygen and carbon dioxide increase
477. Higher plants take up nitrogen as
(a) Nitrites only
(b) Nitrates and ammonia
(c) Nitrates only
(d)Urea
478. Green plants in the sea are useful for the respiration of fish because
(a) They give out carbon dioxide
(b) They give out oxygen
(c) They give out oxygen and carbon dioxide simultaneously
(d) They take oxygen and give out carbon dioxide
479. Stripes on the back of animals are an indication of the
(a) Matching of the skin colour with the surroundings
(b) Mating habit
(c) Food habit
(d) Cave dwelling
480. Which of the following is a balanced fertiliser of plants ?
(a) Urea
(b) Compost
(c) Nitrates
(d) Ammonium sulphate
481. Which of the following is not immunised by ‘Triple Antigen’ ?
(a) Whooping cough
(b) Typhoid
(c) Tetanus
(d) Diphtheria
482. Milk fever in cows occurs due to the lack of
(a) Calcium
(b) Phosphates
(c) Iron
(d) Iodine
483. After hatching by tire hen, the young chicks come out of eggs within
(a) Three weeks
(b) One week
(c) Two weeks
(d) Four weeks
484. Which one of the following is a fast growing tree ?
(a) Teak
(b) Banyan
(c) Coconut
(d) Eucalyptus
485. The decrease in white blood cells results in
(a) The increase in antigens
(b) The decrease in antibodies
(c) The increase in antibodies
(d) No change in antibodies
486. Reserpine derived from the plant Rauwolfia serpentina is used to
(a) Alleviate high blood-pressure
(b) Alleviate pains
(c) Alleviate low blood pressure
(d) Cure rickets