238. Saliva in man is : [RRB 1991]
     (a) acidic
     (b) alkaline
     (c) neutral
     (d) None of these
Ans: (b)
239. Which of the following statements about liver are true?
          1) It secretes bile enzyme.
          2) It forms fibrinogen that helps in clotting of blood.
          3) It produces heparin which prevents blood clotting in blood vessels.
          4) It is a affected by excessive alcohol intake.
     (a) 1 and 4
     (b) 1, 2 and 3
     (c) 1, 2 and 4
     (d) 1, 2, 3, and 4
Ans: (d)
240. The main constituent of haemoglobin is :
     (a) iron
     (b) magnesium
     (c) calcium
     (d) chlorine
Ans: (a)
241. Retina in the eyes acts as a:
     (a) lens in the camera
     (b) shutter in the camera
     (c) film in the camera
     (d) None of the above
Ans: (c)
242. Blood does not clot in the absence of Vitamin K because it is :
     (a) essential for synthesis of prothrombin
     (b) essential for synthesis of fibrinogen .
     (c) an essential component of the clot
     (d) an essential component of the platelets
Ans: (a)
243. The proportion of red blood corpuscles and white blood corpuscles in human body is: [CBI 1992]
     (a) 5 : 1
     (b) 10 : 1
     (c) 500 : 1
     (d) 5000 : 1
Ans: (c)
244. Which of the following is known as "graveyard of RBCs"?
     (a) Liver
     (b) Bone marrow
     (c) Spleen
     (d) Appendix