Speciation that results from the formation of a geographic feature that isolates some members of a population from other members is an example of:
a. allopatric speciation
b. directed speciation
c. stabilizing speciation
d. sympatric speciation

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

Based on her survey, which advertising mediums will work best to publicize leslie's in-store specials?

Read this summary of a scientific theory: "cells are the most basic structural and functional units of life. all living organisms are made up of one or more cells. all cells that are alive in the world today came from pre-existing cells." which of the following would require this theory to be modified? -a.) a survey finds that a majority of people believe viruses carry out the basic processes of life. -b.) a prominent scientist says she feels strongly that one day the theory will be challenged by life on other planets. -c.) the dna of unicellular and multi-cellular organisms is shown to have many fundamental similarities. -d.) scientific observations show that microscopic organisms living in the deep ocean are not made up of cells.