Complex networks of interactions occur again and again in biological systems. Asymptotic techniques provide us with a systematic method of exploiting the wide range of time scales that these networks often operate over. They enable us to break networks down into subsets of reactions that dominate at particular points in time.
Ward, Dunster, Derks, Mistry and Salazar, (2016). Predicting tyrosinaemia: a mathematical model of 4-hydroxyphenylpyruvate dioxygenase inhibition by nitisinone in rats. Mathematical Medicine and Biology.