<prompt> The major contribution to the semen from:TestesSeminal vesiclesProstateBulbourethral and urethral glands  <response>: Semen which is ejaculated during male sexual act is composed of fluid and sperm.vasdeferens-10seminal vesicles-60-mucoid consistencyprostate gland-30-milkyso the bulk of semen is seminal vesicle fluid 