When did the caste system evolve into a four tiered hierarchy

What is associated with mid-ocean ridges?

Which of the activities listed below could limit global warming by slowing the increase in atmospheric carbon dioxide levels? view available hint(s) select all that apply. a. replacing fossil fuels with nuclear energy b. burning vegetation to clear land for agriculture c. limiting soil erosion so organic matter takes longer to decompose d. choosing a fuel-efficient car, or bicycling to school or work e. using more electrical appliances and cars f. cutting down forests to build houses

City in lebanon once known as the "paris of the middle east"