Describe two varieties of amphibian development that do not involve metamorphosis

Metamorphosis is a profound change in structure from one stage to the next in the life history of an organism. The result of metamorphosis may be change to the organism’s entire body plan, such as a change in the animal’s number of legs, its means of eating, or its means of breathing. The two kinds of metamorphosis are complete and incomplete metarmorphosis. Two varieties of amphibian development that do not involve metamorphosis are; (i) some amphibians hatch from the egg as a small version of the adult without going through a larval stage and  (ii) some salamanders remain in the larval stage for their entire life.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).