Stem cells possess the unique ability to divide asymmetrically, a fundamental mechanism that ensures both the maintenance of the stem cell pool and the generation of specialized differentiated cells needed for tissue growth and repair. During asymmetric stem cell division, a single stem cell divides to produce two daughter cells with distinct fates: one daughter retains stem cell properties (self-renewal), while the other commits to differentiation.

This division contrasts with symmetric division, where stem cells yield two identical daughters, either both stem cells or both committed to differentiation, affecting homeostasis differently.

Asymmetric cell division is orchestrated by the unequal segregation of cellular components, such as cytoplasmic proteins and organelles, and the orientation of the mitotic spindle aligned with cell polarity axes. One well-studied example includes the segregation of the protein Numb, a Notch signaling inhibitor, to only one daughter cell, which promotes differentiation of that daughter while maintaining stemness in the sibling.

This division mode maintains a delicate balance; the self-renewing daughter replenishes the stem cell population, while the differentiating daughter allows for tissue development. Disruption of this balance may lead to developmental abnormalities or tumorigenesis.

Therefore, the correct statement about asymmetric stem cell division is:

(2) During asymmetric stem cell division, only one of the daughter cells is retained as a stem cell.

This principle is paramount for understanding stem cell biology, tissue homeostasis, and mechanisms of disease, and underpins advances in regenerative medicine and cancer research.

Answer: (2) During asymmetric stem cell division, only one of the daughter cells is retained as a stem cell.