New farming techniques led to the growth of cities.
did not mean easy farming.

Food can come from sustainable or unsustainable resources. why has the united nations suggested that bugs could be a better source of food than animals like pigs or cattle?

Match the mountains with the type of collision that formed them. a. andes b. aleutians c. north american cordillera d. appalachians 1. continental- continental 2. continental- oceanic 3. oceanic- oceanic 4. arc- continent

Which country has the largest salt flats in the world