Amphibians newts and salamanders....

 Amphibians:Amphibians are so named because most species live both in water and on land. For instance in frogs, the young stages (tadpoles) live in the water and have gills to breath whereas the adult breaths through its moist skin as well as through lungs and usually lives in and around water. Some of the early amphibians, known only from fossils, had scales but the survivors of the class, all falling in the subclass Lissamphibia, lack scales and are smooth.

Newts:

—A newt is an aquatic amphibian of the family Salamandridae, although not all aquatic salamanders are considered newts. Newts are classified in the subfamily Pleurodelinae of the family Salamandridae, and are found in North America, Europe and Asia. Newts metamorphose through three distinct developmental life stages: aquatic larva, terrestrial juvenile (called an eft), and adult. Adult newts have lizard-like bodies and may be either fully aquatic, living permanently in the water, or semi-aquatic, living terrestrially but returning to the water each year to breed.

—Like all members of the order Caudata, newts are characterised by a frog-like body with four equal sized limbs and a distinct tail. Aquatic larvae have true teeth on both upper and lower jaws, and external gills.[2] They have the ability to regenerate limbs, eyes, spinal cords, hearts, intestines, and upper and lower jaws. Recently it was discovered that the Japanese fire belly newt can regenerate its eye lens 18 times over a period of 16 years and retain its structural and functional properties. [3] The cells at the site of the injury have the ability to de-differentiate, reproduce rapidly, and differentiate again to create a new limb or organ. One theory is that the de-differentiated cells are related to tumour cells since chemicals which produce tumours in other animals will produce additional limbs in newts.[4]

 Life cycle of frogs:

 The life cycle of a frog starts with an egg. A female  lays gelatinous egg masses containing thousands of eggs, in water. Each specie  lays eggs in a distinctive, identifiable manner. An example are the long strings of eggs laid by the common American toad. The eggs are highly vulnerable to predation, so frogs have evolved many techniques to ensure the survival of the next generation. In colder areas the embryo is black to absorb more heat from the sun, which speeds up the development. Most commonly, this involves synchronous reproduction. Many individuals will breed at the same time, overwhelming the actions of predators; the majority of the offspring will still die due to predation, but there is a greater chance some will survive. Another way in which some species avoid the predators and pathogens eggs are exposed to in ponds is to lay eggs on leaves above the pond, with a gelatinous coating designed to retain moisture. In these species the tadpoles drop into the water upon hatching