Final answer:
The ductus deferens is distinguished by its thick muscular wall containing three muscle layers.
Step-by-step explanation:
The structural feature that best distinguishes the ductus deferens from the other genital ducts is its thick muscular wall containing three muscle layers.
The ductus deferens, also known as the vas deferens, is a pair of thin tubes that transport sperm from the epididymis to the ejaculatory ducts in the male reproductive system. The muscular wall of the ductus deferens allows it to contract and propel sperm forward.