What percentage of the world's population is expected to live in urban areas by mid-century?

• 60%

• 80%

• 70%

• 50%

What major development allowed humans to form semi-permanent villages?

• Development of language

• Invention of the wheel

• Discovery of fire

• Selective breeding and early agricultural techniques

Why did ancient cities have high population densities?

• Abundance of clean water

• Advanced medical facilities

• Lack of transportation

• Wide availability of land

What infrastructure development helped the Roman Empire overcome urban limitations?

• Advanced irrigation systems

• Sanitation departments

• Road networks

• Electricity distribution

What is one proposed solution for future food production in cities?

• Importing all food

• Vertical farms and skyscrapers

• Relying on rural areas

• Traditional farming