• Biology - Section 1
51. 

Pigmentation of skin is due to

A. lymphocytes
B. monocytes
C. leucocytes
D. melanocytes

52. 

Norepinephrine increases

A. respiration
B. urine production
C. saliva production
D. blood pressure

53. 

Monocot root differs from dicot root in having

A. open vascular bundles
B. scattered vascular bundles
C. well developed pith
D. radially arranged vascular bundles

54. 

Night blindness is cause by lack of which vitamin?

A. Vitamin A
B. Vitamin B
C. Vitamin C
D. Vitamin D

55. 

Radioactivity is a phenomenon of the spontaneous emission of

A. protons (alpha particles)
B. electrons (beta particles)
C. gamma rays (short wave electromagnetic waves)
D. All of the above