Correct option is B
Explanation-
In asymmetric division, one daughter cell remains a stem cell (self-renewal), and the other becomes a progenitor/differentiated cell. This maintains the stem cell pool while generating specialized cells. It is common in tissues with high turnover (e.g., skin, intestines, blood). So, the correct option is b.
Incorrect Options-
Option a: "Stem cells cannot be maintained in culture since they require a distinct in vivo microenvironment known as niches."
This was historically believed to be true, but modern stem cell biology has overcome this barrier. Stem cells can be maintained and propagated in vitro (in the lab) using specially designed culture systems that mimic their niche.
Example: Embryonic stem cells and induced pluripotent stem cells (iPSCs) are routinely cultured.
Option c: "Stem cell-derived transit-amplifying cells are differentiated cells which retain the capacity to divide further."
Transit-amplifying cells are progenitor cells, not fully differentiated. They divide rapidly for a few cycles before differentiating. Once differentiated, cells typically lose the ability to divide.
Option d: "Hematopoietic stem cells (HSCs) are totipotent stem cells."
HSCs are multipotent, not totipotent. They can give rise to all blood cell types, but not to all body tissues or an entire organism. Totipotent stem cells (e.g., zygote, early embryonic cells) can form both embryonic and extra-embryonic tissues (like placenta).
Correct Answer: Option b
