1. Life Span &Life Expectancy Done: by Deidre Brown

2. Life expectancy  Life expectancy is a statistical average of the number of years a human is expected to live.  This is the average amount of years that an individual has before he or she dies. Which begins from the pre-natal period to the senescence period (old age)

3. Life Span  This is the maximum time period of a individual that is observed within a group

4. Factors Influencing life Span & life Expectancy  Availability and cost of medical care :- This factor mostly affect persons who are below the poverty level. Seeing that health is expensive and individuals cant offered health insurance or medicine to aid in the treatment of sickness or dieases.

5.  Health and sanitation levels:- if a country has high level of improper disposal of solid waste, industrial waste and untreated sewage. This will result in the country having high levels of air borne and water borne diseases. This will affect both the elderly and the adolescence.  Poverty:-Poor people can't afford healthy food, clean drinking water, top-notch medical care so this will cause persons to commit suicide or be involve in theft related crimes. Which leads us to our next factor.

6.  Violence:- this reduces the life span and life expectancy by the continuous increase in the level of violence in each country  Lifestyle:- If you are gay, are an IV drug user or engage in other types of high risk behavior, you reduce your life expectancy substantially

7.  Genetic Disease:- these are diseases that are passed down from one generation to the next. Example of these are cancer, diabetes hypertension etc

8. Calculating life expectancy  Life expectancy is calculated using a statistical tool called a life table. A life table is generated from current age- and sex- specific death rates in a given population. The resulting values are used to estimate the likelihood of someone in a hypothetical population dying before their next birthday.  Calculating a person’s life expectancy is based on death patterns in the population, and assumes that current death rates will persist throughout that person’s life.

9. figure 1.Life expectancy (years) at birth by sex, 1901–1910 to 2010–2012