These are the most frequently used words in this book.
abortion
adult
age
although
among
animals
another
baby
behaviour
between
biological
birth
body
boys
brain
breast
case
cells
cent
century
change
child
children
chimpanzees
come
day
death
different
disease
during
early
egg
even
evolution
family
female
few
first
found
generation
girls
give
great
group
human
individual
infant
intercourse
less
life
likely
little
live
long
love
male
man
marriage
may
men
might
milk
million
mother
need
new
now
number
often
old
own
parents
part
partners
people
per
population
pregnancy
seems
sex
sexual
should
social
society
species
still
take
three
time
today
together
two
use
used
woman
women
world
years
yet
young