A) Norms | B) Pollutants |
C) Factors | D) Standards |
Explanation:
From the given passage it is evident that we have to take the word filling the blanks in relation to the word ‘emission’ which means the production and discharge of something, especially gas or radiation. ‘Norms’ refer to a standard or pattern, especially of social behaviour, that is typical or expected. Thus ‘emission norms’ cannot be a correct term as it is not related social behaviour. ‘Pollutants’ mean a substance that pollutes something, especially water or the atmosphere. If this word is used in the given first blank it does not provide the correct term being defined. ‘Factors’ refer to a circumstance, fact, or influence that contributes to a result. ‘Standards’ refer to a required or agreed level of quality or attainment. ‘Limits’ means a restriction on the size or amount of something permissible or possible. Of all the given options ‘factors’ and ‘standards’ can be seen as the most appropriate words for the given blanks. But an emission factor is a representative value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant. Thus, option D is the best fit answer for the given blanks