[3월 학평] 기출변형_내신대비_고1_33번

33번. But for this kind of “breathing” to work properly, the frog’s skin must stay moist.Scientists believe that the frogs’ ancestors were waterdwelling, fishlike animals.

The first frogs and their relatives gained the ability to come out on land and enjoy the opportunities for food and shelter there. ①But they still kept many ties to the water. ②A frog’s lungs do not work very well, and it gets part of its oxygen by breathing through its skin. ③And so the frog must remain near the water which it can take a dip every now and then to keep from drying out. ④Frogs must also lay ..........