In you study rock strata, and in you study fossils.

Petrology and paleontology

Explanation: Petrology refers to the branch of geology that deals with the study of the rocks, and the necessary conditions under which these rocks forms. It involves the study of the minerals that combines to form a characteristic rock, and their mode of occurrence, physical and chemical properties, composition, structure, all in thin sections as well as in hand specimens.

Paleontology refers to the branch of geology that deals with the study of the dead ancient organisms which are commonly known as fossils. This fossils are found to be embedded in the sedimentary rocks. This study of fossils helps in understanding the type of organisms that existed in the past and their food habitat, as well as the type of environment

it would be b. 6co2 + 6h2o --> c6h12o6 + 6o2