hot air: air that has been heated and tends to rise
air: a mixture of gases (especially oxygen) required for breathing; the stuff that the wind consists of
welwitschia: curious plant of arid regions of southwestern Africa having a yard-high and yard-wide trunk like a turnip with a deep taproot and two large persistent woody straplike leaves growing from the base; living relic of a flora long disappeared; some may be 700-5000 years old