Dead zones in oceans refers to
A. Mariana trench, the deepest part of the ocean where living organisms have not been found
B. Hydrothermal vents that have extreme temperatures
C. Neritic zone at extreme end of continental shelf that is devoid of sunlight
D. Oceanic regions that are extremely hypoxic due to substantial eutrophication
Answer: Option D
Ozone depletion is caused by the increase in the level of
A. Water vapour
B. Chlorofluro carbon (CFC)
C. Oxygen
D. Carbon monoxide
Which of the following is a beneficial activity of microorganisms?
A. Some microorganisms use carbon dioxide
B. Some microorganisms provide nitrogen for plant growth
C. Some microorganisms are used in sewage treatment
D. All the above
Which of the following parameters indicates the organic pollution of a water sample?
A. pH
B. Turbidity
C. Hardness
D. COD
The chemical system for removal of the ions of level of salt is called
A. Ion transfer
B. Ionization
C. Ion exchange
D. Ion vaporization
Join The Discussion