Science — CBSE Class 10 board question

(i) Testes are located outside the abdominal cavity in a pouch called the scrotum, because sperm formation requires a temperature slightly lower than body temperature.

Two functions of testes:

1. Production of sperms (male germ cells).
2. Secretion of the male hormone testosterone.

(ii)

1. If the egg is fertilised: The zygote divides and forms an embryo, which implants in the thickened uterine lining. The lining is maintained to nourish the embryo; pregnancy continues for approximately nine months.

1. If the egg is not fertilised: The uterine lining breaks down and sheds along with blood vessels. This causes menstruation, which lasts for a few days.

(iii) In males, the vas deferens is blocked/cut surgically (vasectomy) to prevent sperm transfer. In females, the fallopian tube is blocked/cut surgically (tubectomy) to prevent the egg from reaching the uterus. In both cases, fertilisation cannot occur.

Source: Chapter 7 — How do Organisms Reproduce?, Section 7.3.3

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• (i): Examiners expect the reason for scrotal location (temperature) and both functions — sperm production AND testosterone secretion. Missing either costs marks.
• (ii): Two distinct scenarios must be addressed separately. Key terms: zygote → embryo → implantation for (1); menstruation/shedding of uterine lining for (2).
• (iii): Name the specific structure blocked in each sex and state the outcome (fertilisation prevented). "Vasectomy/Tubectomy" as terms are acceptable but not mandatory for CBSE Class 10.