What does Marlow imply is the basis for his ability to respond to the African natives he observes? To what extent does he here invoke the distinction often made between nature and culture, primitive and civilized? Does he accept that distinction?

Yikes, there is too much to write on this for this space. Marlow never subscribed to the whole idea of "noble imperialism" which set him apart from other white Europeans. While Marlow was far from perfect, he did have a sense of human decency which extended to the African population. He does feed the starving and treats his Cannibal crew a little better than most other whites. Still, the exact distinctions that Marlow draws are far more complex.