Formative Practice 15.4 (Form 4 Biology Textbook Exercise and Answer)


Question 1:
Explain the early developmental process of the embryo.

Answer:
The process of early embryonic development
• The zygote divides many times by mitosis.
• The zygote forms a solid ball of cells called morula.
• Morula forms a hollow sphere known as blastocyst.
• Blastocyst then develops into an embryo.

Question 2:
What is the main function of the HCG hormone?

Answer:
The main function of HCG is to ensure that the corpus luteum continues to function, that is, to produce oestrogen and progesterone in the early stages of pregnancy.

Question 3:
Describe the function of the placenta.

Answer:
The placenta functions as an endocrine organ that secretes progesterone and oestrogen. It also serves as the site for material exchange between foetus and mother.

Question 4:
State what might happen if maternal blood mixes with foetal blood.

Answer:
The placenta is formed from the mother’s endometrial tissue and embryonic tissue that allows materials to diffuse across it. If there’s a mixture of foetus’ and mother’s blood, agglutination may occur if the mother’s blood group is different from that of the foetus.

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