Question

II. Insert correct words or word-combinations. First letters are given. Write the whole word in the answer.

tries to bring to l all the changes

Dozens of rships of different nations

the land have been carefully s.

the depths of the seas b

designed for complicated ocean research are c the oceans.

has been very t explored.

O, the science of oceans, tries

that take place in the physical and chemical pof water at various depths.

The oceans c 147 million square miles

of the e of 197 million square miles.

Yet, the nature of the ocean was practically u until recently

careful mapping did d new details of the ocean waters.

when new t and careful mapping

The surface c have been charted,

Geographically, this vast eof water