Chromosomes line up in the
middle with the
help of centrioles
and their spindle
fibers

How is ribosomal rna useful as a molecular clock? a. a large portion of the dna ring is not vital to structure or function, allowing it to accumulate neutral mutations. b. its rate of mutation increases over time as organisms continue to evolve and differentiate from each other. c. a slow mutation rate makes it useful for determining evolutionary relationships between ancient species. d. it is only found in select organisms, making it easier to compare relationships between species that have it.

Which kind of mutation has occurred when the codon for an amino acid is changed to a stop codon? a. a silent mutation b. a missense mutation c. a frameshift mutation d. a nonsense mutation

*a mastectomy is the surgical removal of one or both breasts, either partially of fully. an oophorectomy is the surgical removal of an ovary or ovaries. analyze a woman’s risk of dying of cancer if she carries a mutated brc1 gene. how do heredity and inheritance relate to the data presented in these charts? what data would you need to see in order to draw conclusions about the effectiveness of preventive surgeries? what does the age at diagnosis tell you about the mutation? explain how breast-cancer genes are still present in the population, despite cancer-related surgeries and deaths.