Have you ever wished you could transform yourself into a completely different kind of being? Orperhaps you’ve dreamed of being able to live and breathe underwater as well as in the open air. For onegroup of animals, amphibians, these capabilities are no flight of fancy but are actually a way of life.Frogs, toads, newts, and salamanders are all members of the amphibian family. The word“amphibian,” derived from Greek, literally means “dual life,” referring to the fact that these animals liveboth in the water and on land. They are generally viewed as one step up the evolutionary ladder from fish.Being cold-blooded, amphibians rely on external sources of energy like sunlight to heat up their bodies,unlike warm-blooded animals such as mammals, which regulate their body temperature internally. Thismeans that amphibians struggle to survive in cold climates and tend to hibernate in the winter months,when their main food sources such as insects are also scarce.Another particular characteristic of amphibians is their ability to breathe through their skin. Whilemost species of amphibian possess lungs, salamanders lack these organs altogether and get their supply ofoxygen solely through their skin. The life cycle of all amphibians starts underwater, and only once they’vereached adulthood can they move onto land. This transition comes about through a drastic process ofmetamorphosis, in which their form completely changes. Each kind of amphibian undergoes this processin its own distinctive way, which only adds to the fascination of these unique creatures.Of all the various species of amphibian, frogs are the best-known. We are perhaps all familiar withthe frog’s life cycle and its particular type of metamorphosis. Once they’ve hatched from eggs underwater,frogs spend the first stage of their life as tadpoles. Tadpoles live exclusively underwater and breathethrough gills, just like fish. Starting off about the size of a pea, they gradually grow, developing first hindlegs, then front legs, before losing their gills and eventually growing lungs. Depending on the kind of frog,this tadpole stage can last anywhere from a week to a few months.A number of frog species protect themselves by secreting toxins from their skin. In frogs, brightcolored skin usually serves to advertise this poisonous nature, so the more colorful a frog is, the more waryyou should be of touching it! In comparison to multi-colored frogs, toads are rather ugly in appearance.Many people assume that toads are a completely separate type of amphibian, but they are actually justanother kind of frog. Apart from their skin being rougher, they have shorter hind legs than frogs, whichmeans they walk rather than hop.Compared to many other animals, amphibians are especially sensitive to changes in their surroundingenvironment, and as such they are seen as valuable ecological indicators. Their moist skins, through whichthey breathe, provide little defense against harmful chemicals. Thus, increased pollution has led to adramatic decline in the worldwide amphibian population in recent years. Unless something is done to cleanup our environment, we risk losing these precious animals to extinction.
29. Which of the following is NOT a feature of amphibians?
(A) They can breathe through their skin.
(B) They can control their body temperature.
(C) They spend the first part of their life underwater.
(D) They often eat insects.