lands on each vas deferens that produce fluids that mix with the sperm to make semen

It seems like you're asking about the glands that contribute to the production of semen. Here's a step-by-step explanation:

1. The Vas Deferens: This is a long, muscular tube that travels from the epididymis into the pelvic cavity, to just behind the bladder. The vas deferens transports mature sperm to the urethra in preparation for ejaculation.

2. Seminal Vesicles: These are the first set of glands that the vas deferens encounters once it enters the pelvic cavity. The seminal vesicles produce a sugar-rich fluid (fructose) that provides sperm with a source of energy and helps with the sperms' motility (ability to move). The fluid of the seminal vesicles makes up most of the volume of a man's ejaculatory fluid, or ejaculate.

3. Prostate Gland: The urethra runs through the center of the prostate gland, which produces additional fluids that contribute to the semen. The prostate gland's secretion is milky and alkaline, which helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm.

4. Bulbourethral Glands: Also called Cowper's glands, these are two small glands located along the urethra below the prostate gland. These glands produce a clear, slippery fluid that empties directly into the urethra. This fluid serves to lubricate the urethra and to neutralize any acidity that may be present due to residual drops of urine in the urethra.

All these fluids mix with the sperm to make semen, which is then ejaculated through the penis during sexual climax.