Ageing gracefully Part II Explaining Ageing :At the biological level, ageing results from the impact of the accumulation of a wide variety of molecular and cellular damage over time. This leads to a gradual decrease in physical and mental capacity, a growing risk of disease and ultimately death.The study of the elderly and aging helps us understand problems in a state of the life course we all hope to reach. Biological aging refers to the physical changes that accompany the aging process, while psychological aging refers to the psychological changes that occur.(A) Aging global population:There were 703 million(70.3 crores) persons