What functional-level strategies has amazon pursued to boost its efficiency? what functional-level strategies has amazon pursued to boost its customer responsiveness? what does product quality mean for amazon? what functional-level strategies has amazon pursued to boost its product quality? how has innovation amazon improve its efficiency, customer responsiveness, and product quality? do you think that amazon has any rare and valuable resources? in what value creation activities are these resources located? how sustainable is amazon's competitive position in the online retail business?