33-scientists-believe-that-frogs-ancestors-were-water-dwelling-fishlike-animals-first-frogs-their-re

Question

33. Scientists believe that the frogs' ancestors were
water-dwelling, 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. But they
□ □ □. A frog's lungs do not
work very well, and it gets part of its oxygen by breathing
through its skin. But for this kind of "breathing" to work
properly, the frog's skin must stay moist. And so the frog
must remain near the water where it can take a dip every
now and then to keep from drying out. Frogs must also lay
their eggs in water, as their fishlike ancestors did. And eggs
laid in the water must develop into water creatures, if they
are to survive. For frogs, metamorphosis thus provides the
bridge between the water-dwelling young forms and the
land-dwelling adults. [3점]

① still kept many ties to the water
② had almost all t□□□□□ds
□□□□□
* metamorphosis: 탈바꿈

Qanda AI · Answer

이 지문에서는 개구리가 물고기 같은 조상에서 진화했고, 비록 육지 생활이 가능해졌지만 완전히 물과 분리되지 못함을 보여 줍니다. 특히 **개구리는 피부 호흡을 위해 몸을 항상 축축하게 유지해야 하고**,

문제 이해