Here below listed are the important aspects about Unit SIX.

The Secrets of a Very Long Life

The word "longevity" is sometimes used as a synonym for "life expectancy" in demography. However, the term longevity is sometimes meant to refer only to especially long-lived members of a population, whereas life expectancy is always defined statistically as the average number of years remaining at a given age. 

Various factors contribute to an individual's longevity. Significant factors in life expectancy include gender, genetics, access to health care, hygiene, diet and nutrition, exercise, lifestyle, and crime rates.

The diets of the three regions are similar in two general ways: ⑴the fruits and vegetables that the inhabitants of the three areas eat are all natural; that is, they contain no chemicals; and ⑵the people consume fewer calories than people do in other parts of the world.  

Diseases Detectives

Modern “disease detectives” include microbiologists, epidemiologists, and other scientists who try to find out the reason for an epidemic—a sickness that many people in one region have.

Genetics

Genes are part of the center (that is, the nucleus)of every cell; in the form of DNA( deoxyribonucleic acid), this “genetic material” determines the characteristics of every living thing—every plant, animal, and human being.

Organ transplants

Organ transplantation is a medical procedure in which an organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organs may be transported from a donor site to another location. Organs  or tissues that are transplanted within the same person's body are called autografts . Transplants that are recently performed between two subjects of the same species are called allografts . Allografts can either be from a living or cadaveric source.