Most
snakebites
are
innocuous
and
are
delivered
by
____________________
species
.
North
America
is
home
to
25
species
of
poisonous
snakes
.
Worldwide
,
only
about
15%
of
the
more
than
3000
species
of
____________________
are
considered
dangerous
to
humans
.
The
family
____________________
is
the
largest
family
of
venomous
snakes
,
and
members
can
be
found
in
Africa
,
Europe
,
Asia
,
and
the
Americas
.
The
family
Elapidae
is
the
____________________
largest
family
of
venomous
snakes
.
In
North
America
,
the
venomous
____________________
are
members
of
the
families
Elapidae
and
Viperidae
,
subfamily
____________________
.
The
subfamily
Crotalidae
(
pit
vipers
)
includes
rattlesnakes
(
Crotalus
and
Sistrurus
)
,
____________________
(
Agkistrodon
)
,
and
copperheads
(
Agkistrodon
)
