4. Although Caecilians have none.
A frog is a amphibian because it has a backbone and because it walks on legs. Any thing that walks on legs are a amphibian.
Yes
A proto-amphibian is an organism that is like, probaly half fish & half amphibian. They appeared in the late Silurian, the time when the fish with jaws evolved legs.
Yes they do back legs. Well really it depends on what animal in the amphibian family is it.
Frog
A "salamander" is a lizard-like amphibian with a broad tail (may or may not exhibit legs).
It is a reptile and because it uses its legs only to swim and it uses its stomach to move in land.
A Mudskipper is a FISH not a reptile or amphibian, it belongs to the gobi family witch is the largest family of fish.
Insects' bodies are divided into three - head, thorax and abdomen and they have 6 legs. Millipedes have a differentiated head but their bodies comprise many identical segments eac with a pair of legs.
4 legs. (think about frogs, toads and newts)
Five.
No birds have four legs. They all have two legs.and if they had four legs they would be like dog with a beak and feathers