Life Expectancy inthe Last Hundred Years

A hundred yearsago,life expectancy in developed countries was about 47;in the early 21 stcentury,men in the United Statesand the United Kingdomcan expect to live to

about 74,women toabout 80, and these______(51)are rising all the time .What hasbrought______(52) these changes?When we look at the life______(53)of people 100years

ago,we need to lookat the greatest______(54)of the time .In the early 20th century,these were theacute and of-ten______(55)infectious diseases such as smallpox.Many

children died veryyoung from these diseases and others,and the weak and elderly were always atrisk.

Inthe______(56)world these diseases are far______(57)today,and in some cases havealmost disappcarcd.A number of______(58)have led to this:improvements insanita-

tion and hygiene,thediscovery and use of antibiotics,which______(59)bacterial diseases much lessdangerous,and vaccinations______(60)common diseases.______(61),

people's generalhealth has improved with improvements in our general environment:cleanerair,better means of preserving food,better and warmer housing,and better

understanding ofnutrition.

Genetically,weshould all be able to live to about 85 but______(62)people do live longertoday,there are still some big killers around that are preventing us fromconsistently

reaching that age.The problems that affect people today are the more chronic illnesses,such asheart disease and strokes,and those______(63)by viruses,such as influenza and

AIDS.Ofcourse,cancer is a huge killer as well.In most cases these diseasesaffect______(64)people,but there are worrying trends in the developed worldwith problems such

asobesity______(65)more heart disease and illnesses such as diabetes at youngerages.

The killers todaycan be classed as"lifestyle diseases",which means that it may bepossiblem to halt their progress.63._________

A.spread

B.affected

C.produced

D.created