The term 'CERTAIN AMPHIBIAN' can be solved by the four letter word 'TOAD'. Toads are amphibians, meaning they are able to live both on land and in water. They are found all over the world and have a wide variety of sizes, colors, and behaviors. Toads are known for their warty skin and long tongues, which they use to catch insects. Toads are also known for their ability to produce toxins, which can be used as a defense mechanism against predators.