Which one of the following is a valid assumption regarding the molecular clock hypothesis in evolution?
A. For a given protein sequence, mutations accumulate at a constant rate in all lineages
B. For a given protein sequence, mutation rates are different in different lineages
C. All proteins evolve at the same constant rate
D. For a given linage, mutation rates are the same for all proteins
Answer: Option A
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
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