生物都有生、老、病、死过程,悉具生理病理机转和死亡转归的科学规律性。健康如何、寿命长短,既取决于内因遗传又关系于外因环境。任何生物,也都有一个有限的最大的寿命,种内个体的平均寿命,比种的最大寿命要短得多。最大寿命,鼠约3年,狗约20年,马约40年,人类约110年种类个体之间,无不存在着很大的差别。 All living creatures are born, aged, sick, and dead. They are all aware of the scientific regularity of physiology, pathology, and death. How health and life span depend on both internal genetics and external factors. Any living creature also has a limited maximum life span. The average life span of an individual in the species is much shorter than the maximum life span of the species. The maximum life span is about 3 years for rats, about 20 years for dogs, about 40 years for horses, and between individuals of about 110 years for humans. There is a big difference.