A characteristic that helps an animal survive is called an adaptation.
Let's take a frog, for example.
It has strong leg muscles to be able to jump out of the water, snatch prey, and return quickly. It has cameoflague to hide itself from predators and sometimes even poison. It has a see-through eyelid of sorts that acts like goggles to let it see underwater and still keep debris out of its eye...et cetera.
Energy comes from making bonds in carbon dioxide and water.
