The zygote formed after fertilisation immediately attaches to the uterus wall. Class 9

The zygote formed after fertilisation immediately attaches to the uterus wall. Class 9

Question 1.

Assertion (A): The zygote formed after fertilisation immediately attaches to the uterus wall. Class 9

Reason (R): The uterus wall is always prepared to receive the zygote.

Choose the correct option:

(i) Both A and R are true, and R is the correct explanation of A.

(ii) Both A and R are true, but R is not the correct explanation of A.

(iii) A is true, but R is false.

(iv) A is false, but R is true.

Answer:

(iv) A is false, but R is true.

Explanation: The assertion is false because the zygote does NOT immediately attach to the uterus wall. After fertilisation in the oviduct, the zygote undergoes a series of mitotic divisions while travelling to the uterus, and it is only after reaching the uterus that it implants into the inner lining. The reason is true that the uterine lining thickens and prepares to receive the zygote after ovulation. Since the assertion is false and the reason is true, option (iv) is correct.