For
starters,
it’s
the
same
as
it
was
3
billion
years
ago.
Comedian
W.C.
Fields
famously
rejected
it
as
the
medium
in
which
fish
conduct
their
reproductive
activities,
but
he
couldn’t
escape
it
entirely.
After
all,
it
comprised
more
than
60
percent
of
his
body,
70
percent
of
his
brain,
80
percent
of
his
blood
and
nearly
90
percent
of
his
lungs.
What
“it”
is,
is
water.
Every
living
thing
needs
water
to
live
—
humans,
who
can
go a
month
without
food,
die
after
just
a
week
without
their
H2O
—
and
every
living
thing
contains
it
to a
significant
degree.
Water
makes
up
75
percent
of
the
average
chicken
and
tree,
for
example,
and
80
percent
of a
pineapple.