Scientist used abstract reasoning to explain something happened
The anwser is South Koren
Answer:
the transformation of their group from a dyad to a triad
Explanation:
In the scenario presented in the context, the relationship between Rebecca and Farah changed as Farah included her new friend, Alison to the group and did all the things or activities which Rebecca and Farah used to do together earlier.
The dyad group of Rebecca and Farah changed to triad when Alison was included in the group which affect the relationship between both the friends Rebecca and Farah.
The Incas had a centrally planned economy, perhaps the most successful ever seen. Its success was in the efficient management of labor and the administration of resources they collected as tribute. Economic exchanges were made using the barter system by which people traded with each other for things they needed.
Great plains is your answer looked it up