Nnegative feedback what does the effector effect?

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Zoo geographic regions are characterized by the presence of specific groups of animals these regions are determined by the taxonomic or phylogenetic relationships of animals. the map shows the zoogeographic regions proposed by the naturalist alfred russel wallace in 1876. the similarities of organisms in which two areas numbered above provide the best evidence for common ancestry between the organisms in both locations ?

Which of the following is caused by reproductive isolation within a species? a. a decrease in gene flow b. an increase in genetic flow c. a decrease in genetic drift d. an increase in gene flow