The correct answer is option (1) because: • Latimeria is a living fossil, it is a bony fish, so (A) matches with (IV). • Echidna is the connecting link between the reptiles and the mammals, so (B) matches with (III). • Vestigial organs are remnants of organs which were complete and functional in the ancestral forms. The vermiform appendix of man is a vestigial organ. So, (C) matches with (II). • Atavism is a trait of distant ancestors that reappears in the modern day, e.g., elongated canine teeth in humans. So, (D) matches with (I). Options (2), (3) and (4) are incorrect as (A), (B), (C) and (D) have incorrect matches in them.