Why do scientists use radioactive decay to determine the age of fossils?

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

To maintain asepsis when administering an injection, all parts of the syringe can be handled except the:

2. which is the last step in the scientific method?