The answer is D.
Traditionally, the groups characterized as untouchable were those whose occupations and habits of life involved ritually polluting activities, of which the most important were (1) taking life for a living, a category that included, for example, fishermen, (2) killing or disposing of dead cattle or working with their hides for a living, (3) pursuing activities that brought the participant into contact with emissions of the human body, such as feces, urine, sweat, and spittle, a category that included such occupational groups as sweepers and washermen, and (4) eating the flesh of cattle or of domestic pigs and chickens, a category into which most of the indigenous tribes of India fell.
Cause: it allows steel to be produced without fuel
effect: lowered the cost of production steel
Through agriculture using the Euphrates river
Answer: The Roman Empire began in 27 BCE when Augustus became the sole ruler of Rome.
Augustus and his successors tried to maintain the imagery and language of the Roman Republic to justify and preserve their personal power.
Beginning with Augustus, emperors built far more monumental structures, which transformed the city of Rome.
Explanation: