Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

Interfacial tension is left unaccounted for by the phase separation model of these entitiesin the limit of low aggregation number, while the predictions of that model converge to the mass action model for higher aggregation number. Their degree of association counts the number of ions in their components, ignoring counterions, while their mass generally refers only to neutral ones and so includes counterions. They never form below the Kraft temperature, but above that temperature they form in a range called the critical concentration; that concentration is irrelevant to inverted ones, which form in nonpolar solvents and result in the hydrophilic heads of their monomers gathering together. Critical to the action of detergents, For 10 points, identify these spherical products of emulsification.

Science