Scientists can learn, which types of organisms were more common during time periods, how species have evolved over time, and the relative age of different species. Sedimentary rocks can contain fossils because, unlike most igneous and metamorphic rocks, they form at temperature and pressures that do not destroy fossil remains. Dead organisms can become sediments which may, under the right conditions, become sedimentary rocks.
A and D are incorrect as these are bonds either between metals and nonmetals or non metals and non metals. C is incorrect as this term is a joining of sugar molecules.
