Although most salamanders have four legs, the aquatic salamander shown below resembles an eel. It lacks hind limbs and has very tiny forelimbs. Propose a hypothesis to explain how limbless salamanders evolved according to Darwin's theory of natural selection.

3 answers

My theory is that the aquatic salamander retreated to the sea for any of various ecological reasons. Water creatures don't need legs.
It's also possible that all salamanders started as sea creatures, and the ones with legs migrated to land because it was beneficial to that species and grew legs in response to their new environment.

What is your hypothesis?
Do a search for "vestigial limbs salamanders" and "limb reduction salamanders evolution." I'd also suggest rereading your text material on natural selection: to answer this question you have to understand that evolution (adaptation and speciation) is the result of selection operating on the expression of random mutations in populations of organisms. If those terms aren't clear to you, your hypothesis probably won't make sense.