On Kepler B#, humanoids have survived every mass extinction as a species for millions of years. On Kepler Bb humanoids haven't been there as long. Only tens of years instead of millions. In my story about Kepler Bb I have Robin and Lisa in a stone age type civilization when they are young, making their own tools(baskets, bows and arrows, spears etc.) 21 years later they go through a fast transition(15 years) from stone age to modern age with people on Kepler B# transporting an interplanetary communicator and modern materials. Now is this feasible or is it just impossible, even in fiction?