These are the most frequently used words in this book.
again
among
animals
another
better
between
big
boys
case
cells
children
come
days
dear
different
does
dr
eat
eggs
even
evolve
evolved
example
fellows
females
few
fight
find
first
fish
flies
genes
genetic
get
girls
give
go
good
groups
having
hermaphrodites
however
humans
individuals
know
known
large
less
let
likely
little
live
long
look
lovers
males
mate
mating
may
means
might
must
mutations
nest
new
nothing
number
often
once
organisms
own
partner
perhaps
population
produce
reason
risk
say
sea
second
see
seem
several
sex
should
since
small
species
sperm
start
still
take
tatiana
though
thus
time
two
want
without
years