Tsunamis at sea __________.

pH is a measure of ___________.

Coastlines of tectonically active regions may be characterized by __________.

Fresh water is most dense at a temperature of about __________.

The rapid decline in the populations of top predator species such as cod, marlin, swordfish, and halibut severely impacts marine ecosystems because _________.

Tropical cyclones form over the ocean and not continents because of the greater source of ____________ heat from the ocean than from continents.

Controls of climate include __________.

In the atmosphere up to an altitude of about 80 km, oxygen (O2) makes up about __________ % and nitrogen (N2) comprises about _________% of the gases by volume.

Coral atolls ____________.

Earth is unique among the planets of the solar system because ____________.