The main civilizations in the americas developed in isolation from the civilizations in africa and eurasia. this allowed civilizations in the americas to advance in some aspects of their development, but to lag behind in other areas such as
a. number systems.
b. writing systems.
c. technology.
d. agriculture.

b) race riots in several cities

answer: this is because archeologists keep finding artefacts and ancient ruins dated more than 10000 to 15000 years, date around scientists said humans discovered language; which is at least mysterious as scientists always have said that is necessary to have a language to have architecture and some basic maths.

explanation: brainlest

australian plates collided into eurasian plates, and the himalayas formed. the andes mountain range the himalayas and the islands of japan form differently. the andes mountain range formed at the convergent boundary of an oceanic plate and continental plate.