ch 13 geo

What percentage of seawater, on average, consists of dissolved salt ions?

3.5%

Approximately what percentage of Earth's surface is covered with water?

70%

Which trench includes the world's deepest sea floor (more than 11 km below sea level)?

Mariana Trench

Of the choices below, which portions of the sea floor are most steeply tilted?

continental slope

Most of the igneous rocks within oceanic abyssal plains are ____________.

covered by clay and the skeletal remains of microplankton

The density of seawater increases with ____________.

decreasing temperature and increasing salinity

As compared to freshwater, saline ocean water is ____________ and therefore provides ____________ support to floating objects.

denser; more buoyant

As compared to continental interiors, surface temperatures in coastal regions ____________.

experience a less extreme range throughout the year

The deepest segments of the ocean floor are found ____________.

in trenches associated with subduction zones

Which type of continental coastline features a much broader continental shelf?

passive continental margins

Compared to continental lithosphere, oceanic lithosphere is ____________.

thinner