Identify the human developmental stage shown below as well as the related right place of its occurrence in a normal pregnant woman, and select the right option for the two, together. [Figure]
- Developmental stage Late morula, Site of occurrence Middle part of Fallopian tube
- Developmental stage Blastula, Site of occurrence End part of Fallopian tube
- Developmental stage 8-celled morula, Site of occurrence Starting point of Fallopian tube
- Developmental stage Blastocyst, Site of occurrence Uterine wall
Answer
(4) Developmental stage Blastocyst, Site of occurrence Uterine wall
Solution
The figure shows an outer layer of cells (trophoblast) enclosing a cavity, with an inner group of cells (inner cell mass) attached on one side ⇒ blastocyst.
As per NCERT, the morula continues to divide and transforms into blastocyst as it moves further into the uterus; the blastomeres are arranged into trophoblast and inner cell mass, and the trophoblast layer then gets attached to the endometrium (implantation).
⇒ Developmental stage: blastocyst; site: uterine wall.
Answer: (4)