You are presented with the question "What do ancathostega have four of?" and the following answer choices: 
- Eggs
 - feet
 - Wings
 - alveoli
 - Lungs
 - ovaries
 - rings
 - Limbs

Now knowing that amphibians are the first true tetrapods, or vertebrates with four limbs and ancathostega is one of the earliest tetrapods found, and by far the most complete, choose the best answer.


 

        Limbs 