21. resistance to the poison warfarin is a genetically determined trait in rats. homozygotes carrying the resistance allele (ww ) have a lower fitness because they suffer from vitamin k deficiency, but heterozygotes (ww) do not. however, the heterozygotes are still resistant to warfarin. in an area where warfarin is applied, the heterozygote has a survival advantage. due to warfarin resistance, the heterozygote is also more fit than the normal homozygote (ww). if the relative fitness values for ww, ww, and ww individuals are 1.0, 0.37, and 0.19, respectively, in areas where warfarin is applied, calculate the allele frequencies at equilibrium. how would this equilibrium be affected if the rats were no longer exposed to warfarin

the darker peppered moth species were favored due to the fact that the industrial revolution had made all the nearby trees a darker color instead of white.

oxygen is the first element in group 16 (via) of the periodic table. the periodic table is a chart that shows how chemical elements are related to each other. the elements in group 16 are said to belong to the chalcogen family. other elements in this group include  sulfur, selenium, tellurium,  and  polonium.  the name chalcogen comes from the greek word  chalkos,  meaning "ore." the first two members of the family, oxygen and sulfur, are found in most ores.

oxygen is by far the most abundant element in the earth's crust. nearly half of all the atoms in the earth are oxygen atoms. oxygen also makes up about one-fifth of the earth's atmosphere. nearly 90 percent of the weight of the oceans is due to oxygen. in addition, oxygen is thought to be the third most abundant element in the universe and in the solar system.