tl;dr Higher activation energy required to activate slip-systems Ductile and brittle are relative terms, since the deformation of a material and the corresponding mode of failure depends on many conditions in addition to crystal structure such a...
Skin cells live about two or three weeks. Colon cells have it rough: They die off after about four days. Sperm cells have a life span of only about three days, while brain cells typically last an entire lifetime (neurons in the cerebral cortex, for example, are not replaced when they die).
Anemia may also result when too many red blood cells are destroyed. Normally, red blood cells live about 120 days. Scavenger cells in the bone marrow, spleen, and liver detect and destroy red blood cells that are near or beyond their usual life span.