Sentence Completion

The phrase ”in all certainty” is awkward and less standard than using the adverb ”certainly”. Option (2) ”is certainly the most important” is the most grammatically correct and natural way to express the intended meaning with strong emphasis.- Rejecting Distractors:- (1) weakens the statement (”appears”). (3) and (4) are awkward combinations (”seems to be certainly”, ”seems to be in all certainty”).

The original sentence uses ”sociology will tell us...”. Option (3) ”Sociology tells us...” maintains the indicative mood and certainty implied by the original sentence, simply changing the tense slightly (present instead of future), which is a common and acceptable paraphrase.- Rejecting Distractors:- (1) adds ”also exist” which isn’t strictly necessary. (2) introduces uncertainty with ”might teach”, contradicting the assertive tone of the original. Contextual Understanding Choosethealternative that best preserves the meaning, certainty, and grammatical struc ture of the original clause being replaced.

The original sentence compares ”customs” (plural) to a region (”the South of In dia”). We need to compare customs to customs. Option (4) correctly uses ”those” (referring to customs) and clarifies the comparison: customs are similar to customs followed elsewhere.- Rejecting Distractors:- (1) uses ”that” (singular) for ”customs” (plural). (2) has the same issue. (3) is grammatically awkward (”South of India’s customs” is less natural than ”customs of the South of India” or ”customs followed in...”).

The correct sentence should be "The human body is like an engine. It required fuel to keep it going." The phrase "to keep it going" makes the most sense contextually as it fits the meaning of the sentence.