Identify the pair of words that best fills the blanks in the sentence in the same sequence:
The continuous application of synthetic pesticides may ________ soil microbial activity, leading to an adverse ________ on crop productivity over time.
Options:
(A) affect, effect
(B) effect, affect
(C) affect, affect
(D) effect, effect
Answer Key:
A
Step-by-Step Solution & Explanation
**Method 1: Semantic and Part-of-Speech Distinction**
1. In the first clause ('may ________ soil microbial activity'), the modal auxiliary 'may' requires a base verb. 'Affect' is a verb meaning 'to act upon or influence'.
2. In the second clause ('an adverse ________ on crop productivity'), the preceding article 'an' and adjective 'adverse' modify a noun. 'Effect' is a noun meaning 'result, consequence, or outcome'.
Thus, the correct sequence is 'affect, effect'. Option **A** is correct.