Endocrine hormones travel throughout the body in the blood, and deficiencies in the Endocrine System are another source of impotence. Given these facts, lack of what in the blood can lead to impotence?  among the following options:
- hormones
 - hemoglobin
 - oxygen
 - iron
 - Energy.
 - t-cells
 - competition
 - Energy


 

 hormones        