The diagram below illustrates the reproductive parts of livestock. Study it carefully and answer the questions that follow. (a) Name the parts labelled I, I...

The diagram is the male reproductive system of livestock (for example, a bull or ram). It shows the paired accessory glands at the top, the central bladder region, the two sperm ducts looping down to the two testes (the round bodies wrapped by coiled bands), and the penis extending below.

(a) Names of the labelled parts

(b) One function of each part

• I - Sperm duct (vas deferens): conveys mature spermatozoa from the epididymis to the urethra during ejaculation.
• II - Testis: produces spermatozoa (male sex cells) and secretes the male sex hormone testosterone.
• III - Penis: serves as the copulatory organ that deposits semen into the female reproductive tract; it also passes out urine.
• IV - Epididymis: stores the spermatozoa and provides the site where they mature and become motile.
• V - Urinary bladder: temporarily stores urine before it is passed out through the urethra.
• VI - Seminal vesicle: secretes a fluid (part of the seminal fluid) that nourishes the spermatozoa and provides the medium in which they swim.

(c)(i) Management practice

The practice is castration (the surgical removal or destruction of the testes of the male animal). By removing the source of sperm and testosterone, the male becomes sterile and loses the urge to mate, so it can no longer breed indiscriminately within the herd.

(c)(ii) The two main parts of utmost benefit

The two parts are the two testes (part labelled II and its pair on the opposite side of the diagram). Because the testes produce both the spermatozoa and the male hormone that drives mating behaviour, their removal during castration stops uncontrolled breeding in the herd.