When we test a hypothesis, we are concerned that the relationship between two variables is not due to alone?

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. the production of sterile male ligers is an example of 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. the production of sterile male ligers is an example of a postzygotic barrier the founder effect sympatric speciation a prezygotic barrier

What is the natural environment? the story of the interaction of people forming societies, cultures, and civilizationsan increase in the world’s temperaturethe process by which social institutions are adopted on a global scalethe natural world in which people, plants, and animals live

Restricting immigrants from entering a country may be based on what belief?