STANDARD Zoology Implantation Assertion Reason Question
Assertion : Implantation is the process of attachment of blastocyst on uterine endometrium. Reason : Implantation is controlled by trophoblast and occurs by decidual cell reaction.
If both the assertion and the reason are true and the reason is a correct explanation of the assertion
If both the assertion and reason are true but the reason is not a correct explanation of the assertion
If the assertion is true but the reason is false
If both the assertion and reason are false
Correct Answer
Detailed Explanation
Implantation is the embedding of the blastocyst into endometrium of uterus. Blastocyst comes in contact with the endometrium in the region of embryonal knob and adheres to it. The surface cells of trophoblast secrete lytic enzymes which cause corrosion of endometrial lining. They also give rise to finger like outgrowth called villi. Villi not only help in fixation but also help in absorption of nutrient. Implantation causes nutrient enrichment, enlargement of cells and formation of uterine part of placenta called decidua.
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