Most of it is fossil water retained in lakes, underground aquifers, and glaciers.
(Most of it; is; fossil water retained in lakes, underground aquifers, and glaciers) (fossil water; retained; L:in lakes, underground aquifers, and glaciers)
Most of it fossil water
is retained
fossil water retained in lakes, underground aquifers, and glaciers
L:in lakes, underground aquifers, and glaciers