Which of the following could lead to desertification?

__________ occurs when electrostatic potential in a thunderstorm becomes great enough to drive electrons across a large expanse of insulating air.

A supercell thunderstorm

A boundary between two air masses is called a(n)

Why do deserts form in polar regions?

The Galveston Hurricane of 1900 was the worst natural disaster in U.S. history, with more people dying than any other disaster when a 15-ft __________ covered the island, whose highest land elevation was 8.7 ft.

Acid precipitation lowered the pH of soil in a terrestrial ecosystem that supported a diverse community of plants and animals. The decrease in pH eliminated all nitrogen-fixing bacteria populations in the area. Which prediction most accurately reflects the impact this will have on the community?

Why is tropical air warmer than polar air?

A coral reef would MOST likely be found

Elephants are not the most abundant species in African grasslands, yet they influence community structure. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands are converted to forests or to shrublands. The newly growing forests support fewer species than the previous grasslands. Which of the following statements describes why elephants are the keystone species in this scenario?