You are presented with the question "What lacks a uterus and vagina?" and the following answer choices: 
- Conifers
 - rats
 - humans
 - mammals
 - echidnas
 - kalenchoes
 - alpacas
 - barnacles

Now knowing that female monotremes lack a uterus and vagina and examples of monotremes are the Platypus and Echidna, choose the best answer.


 

     echidnas    