Final answer:
The seminal vesicles, prostate gland, and bulbourethral glands secrete the majority of the fluid for ejaculated sperm. The seminal vesicles contribute about 70 percent of the semen, and the prostate gland adds nearly 30 percent, with the bulbourethral glands assisting in lubrication.
Step-by-step explanation:
The exocrine glands that secrete most of the fluid in which ejaculated sperm is suspended are the seminal vesicles, prostate gland, and bulbourethral glands. Together, these glands contribute various components to the semen, with the seminal vesicles contributing approximately 70 percent of the semen volume. This fluid is alkaline and provides nutrients for the sperm. The prostate gland adds up to 30 percent of the semen volume with a fluid rich in zinc, which is essential for healthy and motile sperm. Lastly, the bulbourethral glands produce a smaller quantity of fluid that helps lubricate the urethra and neutralize any residual acidity.