text: what are the characteristics of amphibians?   1. air breathing vertebrate with lungs as adults which need to be close to water and land; water esp for reproduction and during their metamorphosis from larva to adult 2. smooth, thin slimey skin thru which most oxygen-co2 exchange takes place; skin is hairless, featherless and scaleless 3. 3 chambered heart- 2 atria, 1 ventricle 4. oviparous, anamniote gel eggs 5. larval stage has gill slits and is aquatic 6. external fertilization