Not sure I’m sorry about that
They're used by humans for fossil fuel and in entertainment. They were not created by the human race, they were created through thousands of being underground and soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock.
... in response to new directions by other persons in leadership in China that Mao thought focused too much on technical expertise and not on ideological purity.
Mao Zedong began the Great Proletarian Cultural Revolution (its official name) in 1966. A big part of the program was the closing of China's schools, because Mao saw the majority of educators as bourgeois types who were failing to support the communist revolution. The Cultural Revolution was an insistence on loyalty to communist party ideology.
The Red Guard was formed, which was made up of high school and college students (no longer attending school, since schools were shut down). These radicalized students became militants for Mao over against those whom he considered not revolutionary enough. The Red Guard destroyed historical artifacts and writings of the of China's former culture. They also attacked persons who were seen to be resisting Chairman Mao's permanent revolution.
