Why were merchants regarded as belonging to one of the lowest social classes, even though they might be wealthy in anceint china

How much water is in the ocean in cubic kilometers

Which layer surrounds the center of the earth? a: crust b: core c: mantle

Effective charts and graphs include all of the following except 1. simple, meaningful, attractive design 2. accurate information 3.at least five different colors 5.clear presentation of information