Asediment core is removed from the floor of an inland sea. the sea has been in existence, off and on, throughout the entire time that terrestrial life has existed. researchers wish to locate and study the terrestrial organisms fossilized in this core. the core is illustrated as a vertical column, with the top of the column representing the most recent strata and the bottom representing the time when land was first colonized by life. in order to assign absolute dates to fossils in this sediment core, it would be most if
a. volcanic ash layers were regularly interspersed between the sedimentary strata.
b. the sediments had not been affected by underwater currents during their deposition.
c. metamorphic rock strata alternated with sedimentary rock strata.
d. we knew the order in which the fossils occurred in the core.
e. fossils throughout the column had equal ratios of a parental radioisotope to its daughter isotope.

A. volcanic ash layers were regularly interspersed between the sedimentary strata.

Explanation:

The discovery of a fossil is a moment of accomplishment for archaeologists, hence the date dating process begins and the older the relic the greater its value for paleontology. Chemistry is present in this process, more precisely the carbon element, but other elements can be used as uranium, lead, potassium and argon.

In the case of the fossils reported in the question, to assign absolute dates to fossils in this sediment core would be most useful if volcanic ash layers were regularly interspersed between sedimentary strata because it would separate sedimentation times and allow the use of more than one element. dating, making the search more complete and the date most credible.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).