Answer:
Up to 24-48 hours
Explanation: according to the FDA
The stem cells divide through mitosis making two daughter cells. One daughter cell becomes a stem wall, and the other daughter cell differentiates into the tissue, so therefore stem cells maintain their populations because mitosis produces a daughter cell that differentiates, as well as one that self-renews, remaining a stem cell. Good luck, and hopefully this helps you out!
0.25 km= 0.25 x 1000m = 250m = 250x100cm = 25,000cm