These are the most frequently used words in this book.
age
aging
already
although
animals
approach
benefits
between
biological
body
book
cause
cells
century
changes
children
claim
consequences
damage
days
death
developed
die
diet
disease
during
early
effects
environment
even
everyone
example
exist
expectancy
extreme
first
food
form
free
future
generation
genes
genetic
health
heart
however
human
important
increase
individuals
ing
known
legends
life
lifespan
lifestyles
live
lived
living
long
longer
longevity
may
medical
medicine
mortality
nature
new
now
often
old
older
order
people
period
population
potential
problem
process
prolongevity
radicals
rates
risk
science
scientific
scientists
species
studies
substances
survival
technology
things
time
tion
today
used
vitamin
world
years
young