== 2024.03.08 ==

A '''theory''' is a [https://en.wikipedia.org/wiki/Reason rational] type of [https://en.wikipedia.org/wiki/Abstraction abstract thinking] about a [https://en.wikipedia.org/wiki/Phenomenon phenomenon], or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as [https://en.wikipedia.org/wiki/Observational_study observational study] or research. Theories may be [https://en.wikipedia.org/wiki/Scientific_theory scientific], belong to a non-scientific discipline, or no discipline at all. Depending on the context, a theory's assertions might, for example, include generalized explanations of how [https://en.wikipedia.org/wiki/Nature_(philosophy) nature] works. The word has its roots in [https://en.wikipedia.org/wiki/Ancient_Greek ancient Greek], but in modern use it has taken on several related meanings.

#Stem cells do not age at the same rate; about one third od chronologically aged HSCs exhibit regeberative function similar to healthy young HSCs, coinciding with the health of mitochondria.

=== Stem cell  ===