The answer is simple: it is the earth that is rotating on its axis once every day.
(the earth; is rotating; ) (it; is; the earth that is rotating on its axis) Context(it is,List([22, 27))):(The answer; is; simple; T:once every day)
it is,List([22, 27))
the earth it The answer
is rotating is is
the earth that is rotating on its axis
simple T:once every day