Fact 1: Testosterone stimulates the reproductive organs to develop into male organs.

Fact 2: Androgens are male hormones, like testosterone.

Given the two facts above, answer the question "What stimulates the reproductive system to form male organs in growth?" with the following options: 
- Chemical energy
 - barnacles
 - Electrical energy
 - a doorbell
 - sensory neurons
 - peachleaf willow
 - Veins and arteries.
 - male hormones


 

        male hormones 