[单项选择]Rocks which have solidified directly from molten materials are called igneous rocks. Igneous rocks are commonly referred to as Line primary rocks because they are the original (5) source of material found in sedimentaries and metamorphics. Igneous rocks compose the greater part of the earth’s crust, but they are generally covered at the surface by a relatively thin layer of sedimentary or metamorphic rocks. Igneous rocks (10) are distinguished by the following characteristics: (1) they contain no fossils; (2) they have no regu- lar arrangement of layers; and (3) they are nearly always made up of crystals. Sedimentary rocks are composed largely of (15) minute fragments derived from the disintegration of existing rocks and in some instances from the remains of animals. As sediments are transported, individual fragments A. Ⅰ only B. Ⅲ only C. Ⅰ and Ⅱ only D. Ⅱ and Ⅲ only E. (E) Ⅰ, Ⅱ, and Ⅲ