Do skin cell have the psen1 gene in them

Cells tend to have a relatively small and uniform size. why aren’t cells larger?

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

Which type of scientific statement is defined as a hypothesis or group of hypotheses that can be accepted as true based on the repeated experimentation with similar results