Assertion: hip hop | /r/HasProperty | marked by four distinct phases
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text: These circumstances are instrumental to the development of rap music, which is marked by four distinct phases: the mobile DJ (c. 1972–1978); the rhyming MC and the emergence of the rap music genre (1976–1978); the early commercial years of rap music (1979–1985); and the explosion of rap in the musical mainstream (1986–present).