You are presented with the question "What group of animals do chordates belong to?" and the following answer choices: 
- graptolites
 - more abundant
 - warm-blooded
 - four limbs
 - epidermal
 - Vertebrates
 - animals
 - insects

Now knowing that chordates have a complete digestive system and a closed circulatory system and vertebrates have a closed circulatory system, choose the best answer.


 

      Vertebrates   