The term metamorphosis comes from the Greek language. Meta- means "change" and morph means "shape." It describes a literal and dramatic change in the form of an organism. A tadpole becoming a frog, a maggot becoming a fly, and a caterpillar becoming either a butterfly or a moth (depending on the species) are all examples of metamorphosis. These changes are usually accompanied by a new set of behaviors and habitat for the organism.
Other animals, like the bear, fish, dog, or humans, do not undergo such drastic changes. Sure, each of these organisms will mature and undergo puberty, which is still a pretty big change, but it will retain the same basic form. Humans, for example, start and end life with a head, an abdomen, two arms, two legs, and no tail.
Metamorphosis means transformation it is a inheritive integritive concept mostly observed in amphibians and insects and is also found in some fish (marine invertibrates).
In simple words we can say the changes observed during transformation from from imamture to mature form that is adult form is called metamorphosis.
So from the above given option dog and bear doesn't undergo metamorphosis, as we can see there is not much changes in the appearence and the texture etc., during there development from imature to mature.
But we can see a huge diference in the moth as well as fish.
a moth start with the egg then caterpiller then transform into cocoon and finally into moth so we can see many forms in the life cycle of moth this is called metamorphosis.
In the same way in the life cycle of fish also we can find many changes undergoing metamorphosis.
Metamorphosis is a profound change in form from one stage to the next in the life history of an organism, as from the caterpillar to the pupa and from the pupa to the adult butterfly.
Moth also comes under the same category!