Reproduction in organisms — BIOLOGY STD 12 Science — Question
Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYReproduction in organisms1 Mark
MCQ
In mammals egg are microlecithal and isolecithal because these are:
A
Oviparous
✓
Viviparous
C
Ovoviviparous
D
None of the above
✓
Answer
Correct option: B.
Viviparous
Mammalian eggs have very little yolk $($microlecithal$)$ because the embryo obtains maternal nutritional support throughout its development.
Isolecithal refers to the even distribution of yolk in the cytoplasm of the ovum in mammals and other vertebrates. In mammals, because the isolecithal cells have only a small amount of yolk, they require immediate implantation onto the uterine wall to receive nutrients.
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