(a) Given below is a diagram of the lateral section of the testis of a man. Study the same and answer the questions which follow:

(i)Label the parts numbered 1 to 4 in the diagram.

(ii) State the functions of the parts labelled 1 and 3.

(iii) What is the significance of the testes being located in the scrotal sac outside the abdomen?

(iv) What is the role played by the inguinal canal?

(v) What is semen?

i. The parts are ; 

1 - Seminiferous tubules
2- Lobule
3 - Epididymis
4- Vas deferens

ii. 1. Seminiferous tubules produce sperms by the process of spermatogenesis.

3. Epididymis stores the sperms for some days during which they mature and become motile.

iii. The scrotal sac provides a lower temperature. The production and survival of sperms require a temperature which is lower than the normal body temperature, so the testes are located in the scrotal sac which is outside the abdomen, which maintains the temperature at 3°C below the normal body temperature.

iv. The inguinal canal allows the descent of testes along with their ducts, blood vessels and nerves.

v. Semen is the mixture of sperms and secretions from the seminal vesicle, prostate gland and Cowper's gland.