Why does sound increase in pitch as a sound source approaches, as demonstrated by the Doppler effect?

originally he was supposed to be dead but they wanted to continue the series so they brought him back to life.

after the roman empire, the catholic church began to unify by taking on many duties of a government.

answer: both considered peasants valued members of society.

explanation: the ancient chinese and indian empires were large asian empires that had the same problems with other big empires, they had to work hard and sometimes fight in order to keep them united, they both relied heavily on their capacity to trade and to send strange and rare items to europe, and had the father as the head of the house hold in both societies, but they didn´t considered pleasants as valued members of their society, they were the bottom of the social pyramid in both of their societies.