Q 01/05

About what share of Earth's surface is dry land?

A) About 4%

B) About 10%

C) About 29%

D) About 60%

Answer · why

C) About 29%

About 29% of Earth's surface is dry land; the ocean covers the other 71%, and because it is deep as well as wide, it is by far the largest living spac...

Q 02/05

Which of the world's oceanic divisions is the largest by area?

A) Pacific Ocean

B) Indian Ocean

C) Atlantic Ocean

D) Arctic Ocean

Answer · why

A) Pacific Ocean

The Pacific Ocean covers about 165 million square kilometres, more than all the planet's land area combined.

Q 03/05

Which traditional unit of six feet do sailors use to measure the depth of water?

A) Furlong

B) Fathom

C) Cubit

D) League

Answer · why

B) Fathom

Fathom comes from an Old English word for outstretched arms, because one fathom is roughly the span between a grown man's fingertips.

Q 04/05

Roughly how deep is the ocean on average?

A) About 37 metres

B) About 370 metres

C) About 3.7 kilometres

D) About 37 kilometres

Answer · why

C) About 3.7 kilometres

About 3.7 kilometres: sunlight fades out within the first 1,000 metres, so most of the seabed lies in permanent darkness.

Q 05/05

What is the average salinity of ocean water?

A) About 0.4%

B) About 1.2%

C) About 3.5%

D) About 11%

Answer · why

C) About 3.5%

About 3.5%: every kilogram of seawater holds some 35 grams of dissolved salts, most of them worn out of rocks on land by rain and carried down to the ...