एक वास्तविक और पूर्ण शून्य बिंदु (true zero point) की उपस्थिति किस मापन पैमाने (measurement scale) की एक परिभाषित विशेषता है?

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: