Final answer:
The prostate gland is the part of the male reproductive system that produces most of the semen, while other glands like the seminal vesicles and bulbourethral glands also contribute to the fluid composition.
Step-by-step explanation:
The part of the male reproductive system that produces most of the semen is the c) Prostate gland. While the testes and specifically the seminiferous tubules within them are responsible for sperm production, the prostate gland, along with other accessory glands like the seminal vesicles and the bulbourethral glands, contribute the majority of the fluid that composes semen. This seminal fluid contains various substances that support and protect the sperm during and after ejaculation, such as nutrients, enzymes, and other compounds crucial for sperm viability and function.
In addition, sperm develop tails and become motile in the epididymis, not the testes or the seminal vesicles. The vas deferens are responsible for transporting sperm from the epididymis to the urethra, from where it is ejaculated. The urethra is the common pathway for both the urinary and reproductive systems in males.