Why is testing ideas an important par of all science and engineering practice?

Which of the following is true of photosynthesis? a)carbon dioxide is a reactant b)water is a product c)most reactions within this process are exothermic d)oxygen is a reactant

Could someone me with number one you

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