Eutrophication in a water body leads to which of the following phenomena? A. Bloom of algae B. Increase in the level of dissolved oxygen (DO) C. Increase in turbidity and odor of the water body D. Difficulty in sustaining normal aquatic life E. Deficiency of nutrients in the water body Choose the correct answer from the options given below:

The approach of combining multiple methods, data sources, or investigators in the study of the same sociological or scientific research phenomenon is known as:

Given below are two statements: Statement (I): The near-complete absence of fluoride in drinking water causes tooth decay. Statement (II): Excessive concentrations of fluoride in drinking water cause mottling of teeth, also known as dental fluorosis. In the light of the above statements, choose the most appropriate answer from the options given below: