In general, how did the types of items traded East (from china) to West differ from the types of items traded West to East?

Why would the crystals in an intrusive igneous rock be larger than the crystals in a chemical sedimentary rock? a. intrusive rocks form beneath the earth's surface, so they cool very slowly, which produces larger crystals. b. chemical sedimentary rocks form from dissolved substances on the earth's surface with very high heat and cool very slowly, which produces smaller crystals. c. chemical sedimentary rocks and intrusive rocks have crystals of the same size. o d. chemical sedimentary rocks form deep in the earth, so they cool slower, which produces small crystals. € read question correct:

Gemstones are commonly found in pegmatites, which are igneous rocks that are a. exceptionally mafic b. exceptionally coarse grained c. exceptionally fine grained d. extrusive, forming from lava

What's erosion? a. the breakdown of rock into smaller pieces b. the removal of weathered products from rock c. a change in rock resulting from exposure to water d. a chemical change in rock that weakens it