2696: Mixture of which one of the following pairs of gases is the cause of occurrence of most of the explosions in mines?
(a) Hydrogen and oxygen
(b) Oxygen and acetylene
(c) Methane and air
(d) Carbon dioxide and methane
2697: With reference to Indian history, which of the following is/are the essential elementy elements of the feudal system?
1. A very strong centralized political authority and a very weak provincial or local political authority
2. Emergence of administrative structure based on control and possession of land
3. Creation of lord-vassal relationship between the feudal lord and his overlord
Select the correct answer using the code given below.
(a) 1 and 2 only
(b) 2 and 3 only
(c) 3 only
(d) 1, 2 and 3
2698: The human immuno deficiency virus (HIV) is a living entity because it can
(a) Excrete in human serum
(b) Disturb host cell respiration
(c) Undergo auto-reproduction
(d) Move from one cell to another
2699: Important oilfields of the Brahmaputra Valley include
(a) Digboi and Kilboi
(b) Lunej and Ankhleshwar
(c) Badarpur and Masimpur
(d) Naharkatia and Moran
2700: With reference to 'Organization for the Prohibition of Chemical Weapons (OPCW)', consider the following statements:
1. It is an organization of European Union in working relation with NATO and WHO.
2. It monitors chemical industry to prevent new weapons from emerging.
3. It provides assistance and protection to States (Parties) against chemical weapons threats.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3