Scientists can determine how much CO 2 existed in ancient air because some of that air is trapped in bubbles inside cores of ice from the Greenland and Antarctic ice sheets.
(some of that air; is trapped; in bubbles inside cores of ice from the Greenland and Antarctic ice sheets) (Scientists; can determine; how much CO 2 existed in ancient air) Context(Scientists can determine,List([0, 24))):(CO 2; existed; L:in ancient air; because some of that air is trapped in bubbles inside cores of ice from the Greenland and Antarctic ice sheets)
Scientists can determine,List([0, 24))
some of that air Scientists CO 2
is trapped can determine existed
in bubbles inside cores of ice from the Greenland and Antarctic ice sheets
how much CO 2 existed in ancient air
L:in ancient air because some of that air is trapped in bubbles inside cores of ice from the Greenland and Antarctic ice sheets