180. Which of the following have the ability to fix atmospheric nitrogen? [IES 1993]
         1) Azolla
         2) E.coli
         3) Cyanobacteria
         4) Azoskirillun
     (a) 1, 2 and 4
     (b) 2 and 3
     (c) 1, 3 and 4
     (d) 1, 2, 3 and 4
Ans: (c)
181. The deficiency of which one of the following gives rise to a disease characterised by oedema, subcutaneous
     haemorrhages, anaemia and pathological changes in the teeth and gums? [CDS 1993]
     (a) Retinol
     (b) Vitamin B complex
     (c) Ascorbic acid
     (d) Cyancobalamin
Ans: (c)
182. Which of the following is known as the queen of spices?
     (a) Coriander
     (b) Cardamom
     (c) Fenugreek
     (d) Chillies
Ans: (d)
183. Which of the following are true of fertilizer? [NDA 1995]
         1) It supplies nutrients to the plants.
         2) It kills the pests.
         3) It produces plant growth hormones.
         4) It adjusts the soil pH and increases the crop yield.
     (a) 1 and 2
     (b) 2 and 3
     (c) 1 and 3
     (d) 1 and 4
Ans: (d)
184. Which of the following is not obtained from the bark of a tree? [Asstt Grade 1993]
     (a) Cinnamon
     (b) Quinine
     (c) Bhang
     (d) Tannin
Ans: (c)
185. Which of the following types of woods is specially used as railways sleepers? [CDS 1994]
     (a) Mahogany
     (b) Ivory Wood
     (c) Greenheart wood
     (d) Jarrahand barri
Ans: (d)
186. Match the following: