Final answer:
The epididymis is the first portion of the duct system in the male reproductive system, and it provides a site for sperm maturation.
Step-by-step explanation:
The first portion of the duct system in the male reproductive system is the epididymis. It provides a site for sperm maturation after they leave the testes.
The epididymis is a coiled tube that collects and stores sperm, allowing them to mature before they pass on to the vas deferens, which then transports the sperm to the ejaculatory ducts.
These ducts are one of many structures that make up the complex male reproductive system. The seminal vesicles and prostate gland are accessory glands that add fluids to the sperm to create semen, which is eventually ejaculated through the urethra during sexual climax.