The effect is due to static electricity when Lucas rubbed plastic ruler on the sweater he caused the ruler to become negatively charged due to rubbing creating a negative charge that is carried by electrons so when he waved above pieces of paper positive charges present in the atoms of paper became attracted to negatively charged ruler.
They are a species that is closely related to, but distinct from, Homo sapiens.
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Answer:
the polluted air coming out from the big industries