Life Science - National Park Service

Explain to the students that in the phyla category there are four classes, amphibians, reptiles, birds, and mammals. Amphibians have moist skin, lay jellylike eggs and spend part of their life cycle in water. They are ectothermic (cold-blooded). Reptiles have scales or horny plates and usually lay leathery eggs. They are also ectothermic. ................
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