Suzy is examining a brass lamp. If brass is a mixture of copper and tin, what can Suzy conclude? A Brass is an impure substance composed of copper, Cu, and tin, Sn.
B Brass is a pure substance represented by the symbol B.
C Brass is a pure substance represented by the symbol Br.
D Brass is an impure substance composed of copper, Co, and tin, Tn.

Which set of characteristics best describes sedimentary rock? a) largest type of rock, made of organic matter, hardest type of rock b) often contains layers, forms near sources of water, contains fossils c) least abundant type of rock, made of other rocks, made mostly of minerals d) most abundant type in earth's crust, made of magma/lava, contains no fossils