When reproducing, Robins (a species of bird) typically lay four eggs. Laying more eggs might result in malnourished chicks and laying fewer eggs might result in no viable offspring. This is an example of

The model illustrates a process by which a substance is taken up by a cell

Read the following scenario to answer the following question. in some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called "ligers." male ligers are sterile but some female ligers are fertile. in the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences. applying the biological species concept, the sterility of ligers reveals that a. lions are probably a subspecies of tigers b. tigers and lions are the same species c. a new species called "ligers" is forming d. tigers and lions are separate species

Compare the composition of the moon's surface with the composition of the earth's surface.