How is velocity more than just speed? what else does it include?

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

What is the term for the two sets of chromatids formed in the parent cell a.haploid b.diploid c.gamete d.tetrad

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