MCQ
Which layer develops first during embryonic development?
- AEctoderm
- BMesoderm
- CEndoderm
- DBoth B and C
✓
Answer
- Endoderm
Explanation:
Once after fertilization, zygote is formed, which then changes to blastocyst having an inner cell mass.
This inner cell mass initially has two layers as epiblast and hypoblast.
After two weeks, primitive streak appears.
The epiblast moves towards the primitive streak and forms a new layer, called as the endoderm as the first layer.
This epiblast keeps moving and forms a second layer and third layer as mesoderm and ectoderm respectively.
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