3866: 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
3867: Operation Flood refers to:
(a) Use of preventive measures for flood devastation
(b) A study about floods
(c) Dairy development for increased milk production
(d) None of these
3868: Biofilms are
(a) colour films used by biologists to photograph living organisms
(b) photomicrographs of microorganisms from various habitats
(c) accumulations of microorganisms at surfaces such as those of a rock, a tooth or an oil droplet
(d) photographic films made through fermentation processes of certain industrial microorganisms
3869: At which one of the following positions shown in the diagram will the height of the ocean tide be maximum ?
(a) M,1
(b) M,2
(c) M,3
(d) M,4
3870: The largest coral reef in the world is found near the coast of which one of the following countries?
(a) Australia
(b) Cuba
(c) Ghana
(d) Philippines