You are presented with the question "Lack of what in the blood can lead to impotence? " and the following answer choices: 
- hormones
 - hemoglobin
 - oxygen
 - iron
 - Energy.
 - t-cells
 - competition
 - Energy

Now knowing that endocrine hormones travel throughout the body in the blood and deficiencies in the Endocrine System are another source of impotence, choose the best answer.


 

 hormones        