1.   Even stock prices rise and fall according to the public perception of how good the leader is.

2.   The voices around him rise and fall according to circumstance and emotion.

3.   There are signs, for example, that the power and the frequency of El Ninos may rise and fall according to vast cycles of the Pacific Ocean.

4.   When it falls, according to the manufacturer, NBGS International of New Braunfels, Texas, it can move faster than many traditional roller coasters.

5.   The number of positions rose and fell according to the length of the missions they dealt with.

6.   It has attracted generations of vulcanologists to its molten lava lake, the level of which rises and falls according to seismic activity.