(a) Watson & Crick
      (b) Hargobind Khorana
      (c) Widel & Tatum
      (d) Margan
Ans: (c)
242. Which one of the following is necessary for the impulse communication in muscular fibre?
      (a) Calcium
      (b) Iron
      (c) Sodium
      (d) Zinc
Ans: (c)
243. Who gave Double Helix Model of DNA?
      (a) Dalton
      (b) Shalk
      (c) Watson & Crick
      (d) Leeuwenhock
Ans: (c)
244. Which of the following instrument measures blood pressure? [BPSC (Pre) 2008]
      (a) Spherometer
      (b) Animometer
      (c) Sphygomanometer
      (d) Ammeter
Ans: (c)
245. Which of the following is a sex-linked disease:
      (a) leprosy
      (b) tuberculosis
      (c) colour blindness
      (d) leukemia
Ans: (c)
246. Colour blindness in the human beings is caused by-
      (a) the excess alcoholism
      (b) defective X-chromosomes
      (c) defective Y-chromosomes
      (d) the deficiency of vitamin E
Ans: (b)
247. Which of the following occurs in Haemophilia?
      (a) haemolysis
      (b) blood doesn"t clot
      (c) RBCsticks
      (d) WBCbecomes cellular trophic
Ans: (b)
248. The technique used to detect the paternal character of the offspring is: [IAS 1997]
      (a) protein synthesis
      (b) chromosome counting
      (c) quantitative synthesis of DNA
      (d) DNA finger printing
Ans: (d)