Shield volcano are cave-like volcanic straights formed by the hardening of overlaying lava. These structures help further the propagation of lava, as the walls of the tube insulates the lava within. Lava tubes can account for a large portion of shield volcano activity; for example, an estimated 58% of the lava forming Kīlauea comes from lava tubes. In some shield volcano eruptions, basaltic lava pours out of a long fissure instead of a central vent, and shrouds the countryside with a long band of volcanic material in the form of a broad plateau. Plateaus of this type exist in Iceland, Washington, Oregon,
What Is Life song offers "little overall coherence between words and music". In a 2010 poll to find the "10 Best George Harrison Songs", AOL Radio listeners voted "What Is Life" third behind "My Sweet Lord" and "Blow Away". A similar list by Michael Galluci of Ultimate Classic Rock placed it second (behind "My Sweet Lord"), as Galluci wrote of the track having "a giant pop hook as its guide" as well as "the catchiest chorus Harrison ever penned".<ref name="Gallucci/UCR">Michael Gallucci, "Top 10 George Harrison Songs", Ultimate Classic Rock (retrieved 28 March 2014).</ref> In 2009, Matt Melis of Consequence of Sound listed it