You are presented with the question "amphibians are the first true what with four limbs?" and the following answer choices: 
- members of their own species
 - to move people
 - warm-blooded
 - Due to their feet
 - animals with backbones
 - remains of prehistoric life
 - Something to move
 - Generating heat

Now knowing that amphibians are the first true tetrapods, or vertebrates with four limbs and animals with backbones are called vertebrates, choose the best answer.


 

     animals with backbones    