30. 다음 글의 밑줄 친 부분 중, 문맥상 낱말의 쓰임이 적절하지 않은 것은?
Europe’s first Homo sapiens lived primarily on large game, particularly reindeer. Even under ideal circumstances, hunting these fast animals with spear or bow and arrow is an ① uncertain task. The reindeer, however, had a ②weakness that mankind would mercilessly exploit: it swam poorly. While afloat, it is uniquely ③ vulnerable, moving slowly with its antlers held high as it struggles to keep its nose above water. At some point, a Stone Age genius realized the enormous hunting ④ advantage he would gain by being able to glide over the water’s surface, and built the first boat. Once the ⑤ laboriously overtaken and killed prey had been hauled aboard, getting its body back to the tribal camp would have been far easier by boat than on land. It would not have taken long for mankind to apply this advantage to other goods.
* exploit: 이용하다 ** haul: 끌어당기다