What outside factor most directly contributed to the formation of enclaves in cities

The correct answer is Housing discrimination

Housing discrimination takes many forms:

A real estate agent shows you apartments in one neighborhood and not another because of your race.

An owner refuses to rent to you due to your Section 8 voucher

An owner makes an inappropriate comment about their gender, ethnicity, religion or disability.

You have small children and the owner says he can't rent it for you because the apartment has lead paint.

the andes or andean mountains (spanish: cordillera de los andes) are the longest continental mountain range in the world, forming a continuous highland along the western edge of south america. this range is about 7,000 km (4,300 mi) long, about 200 to 700 km (120 to 430 mi) wide (widest between 18° south and 20° south latitude), and of an average height of about 4,000 m (13,000 ft). the andes extend from north to south through seven south american countries: venezuela, colombia, ecuador, peru, bolivia, chile and argentina.

from wikipedia

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