If the air contains high levels of pollutants, what effect might this have on water quality?

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?

In sheep, the allele for belly fur (a) is dominant to the allele for no belly fur (a). a mother with the genotype aa and a father with the genotype aa produce an offspring.