Why were asian spices in the 1300s so expensive by the time they reached europe

What kind os source would a historian use to get a firsthand account of a past event

Due to serious dogmatic differences between the orthodox church and the western christan churches, the orthodox church is not in communion with the roman catholic and protestant communities true or false

Which of the following questions must be asked about the use of resources in an economic system a. what allocation will provide the fastest growth b. what is the most secure allocation c. what is the fairest allocation d. what is the most effective allocation