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Human Reproduction — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYHuman Reproduction1 Mark
Question
For two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
Assertion: At the time of implantation, which takes place in 14 days, the human embryo is called blastocyst.
Reason: Implantation occurs in the gastrula stage.
✓

Answer

  1. Both assertion and reason are false.

​​​​​​​​​​​​​​​​​​​​​​​​​​​​Explanation:

Implantation is the attachment of the early embryo, called blastocyst, to the lining of womb. It begins between the fifth and seventh day after the ovulation and is enabled by the secretion of enzymes that digest a portion of the endometrium. A blastocyst is composed of a hollow sphere of trophoblast cells, inside of which is a small cluster of cells called the inner cell mass. Trophoblast goes on to contribute to fetal membrane systems. While the inner cell mass is destined largely to become the embryo and fetus.

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