260 million years ago there was a supercontinet called Pangaea
Answer:
Subsistence agriculture occurs when farmers grow food crops to meet the needs of themselves and their families on smallholdings.
#1) Why do coal-burning power plants and oil refineries have tall smokestacks?
Answer: They are gas combustion devices used in industrial plants such as petroleum refineries, chemical plants, natural gas processing plants as well as at oil or gas production sites having oil wells, gas wells, offshore oil and gas rigs and landfills. In industrial plants, these are primarily used for burning off flammable gas released by pressure relief valves during unplanned over-pressuring of plant equipment.
