This tubuloalveolar structure develops from a narrow section of mesoderm located between the paraxial mesoderm and lateral plate. Healthy function of this structure can be determined with a blood test for levels of kallikrein-3, and rezum water vapor therapy performed if that blood test shows abnormal results. This structure receives circulation from the internal pudendal artery and drains to the internal iliac lymph nodes. The (*) peripheral, central and transition zones make up this organ whose cancers are staged with the aid of a Gleason score. Dihydrotestosterone mediates this organ’s growth, which continues until about age forty. For 10 points, name this singular organ that sits below (10[1])the urinary bladder, surrounds the urethra (10[1])and produces the fluid (10[1])constituent of semen. ■END■