How do index fossils scientists? a. they aid in the study of ranges of different organisms. b. they advance understanding of the origin of life on earth. c. they aid in comparison of rock layers at distant locations. d. they advance understanding of rock type at the time the organism lived.

Whenever diploid populations are in hardy-weinberg equilibrium at a particular locus a) the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change. b) natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency. c) this means that, at this locus, two alleles are present in equal proportions. d) the population itself is not evolving, but individuals within the population may be evolving.