D. There were middlemen for them, as trading was quite common between the groups.
Answer:d
Explanation:because that’s what they do
Answer:
The answer is test-retest.
Explanation:
Test-retest is a method that consists in applying a treatment or measure in two different points in time. This is done in order to strengthen the reliability of the results, as in one situation there might be other factors that interfere with the outcome.
When the measures present similar or the same results, this means the reliability is high.
Answer:
true
I hope it would be helpful