The four mechanisms are as follows:
1) Orographic lifting: Air is forced to rise over a mountainous barrier
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2) Frontal wedging: Warmer, less dense air is forced over cooler, denser air along a front
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<span>3) Convergence: Pileup of horizontal air flow resulting in an upward flow
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<span>4) Localized convective lifting: Unequal surface heating causes localized pockets of air to rise because of their buoyancy. </span><span />
PPLO stands for Pleuropneumonia-Like Organism and it means: Mycoplasma.
Pleuropneumonia means pneumonia complicated with pleurisy.
Mycoplasma means any of a group of small typically parasitic bacteria that lack cell walls and sometimes cause diseases.
(I hope this helps in anyway possible. Sorry if it's not in 100 words, I couldn't get to that number. But maybe you can put more words into the sentences and make them longer. But I do really hope this has helped you!)
