Biology
The diagram given below is that of a developing human foetus. Study the diagram and then answer the questions that follow:
(i) Label the parts numbered 1 to 3 in the diagram.
(ii) Mention any two functions of the part labelled 2 in the diagram.
(iii) Explain the significance of the part numbered 3 in the diagram.
(iv) Define the term 'Gestation'. What is the normal gestational period of the developing human embryo?
(v) Mention the sex chromosomes in a male and female embryo.
Reproductive System
ICSE 2016
ICSE 2020
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Answer
(i) The parts numbered 1 to 3 in the diagram are:
- 1 → Umbilical cord
- 2 → Placenta
- 3 → Amniotic fluid
(ii) Two functions of Placenta are:
- Acts as a barrier and prevents germs from entering foetal blood.
- Secretes Oestrogen and Progesterone.
(iii) Protects the embryo from physical damage by jerks or mechanical shocks, keeps an even pressure all around the embryo and allows the foetus some restricted movement.
(iv) The full term of the development of the embryo in the uterus is called gestation. In humans, it lasts for about 280 days / 40 weeks.
(v) The sex chromosomes in a male and female embryo are:
Male - XY
Female - XX
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