37. For the sake of the logic and coherence of this paragraph, Sentence 6 should be placed:
Your Answer is
Correct Answer is B
Explanation
This sentence means "at first, they are difficult to find". Key words in this sentence: "At first", "they". The turning word but in the first sentence of this paragraph, "But once our eyes get used to the task, they are easy to spot" is a turning relationship with S6, so S6 is placed before S1.