Story time--some listen better than others

After reading an "All about Trains" book before our rest time:

Me: "And which type of engine won the contest?"

Ethan: "The Rocket!"

Me: "Very good, Ethan!  And what did they used to have to use to heat up the engine of the trains?"

Colin: "Wood."

Me: "Yep.  Wood...and what was the problem they had using wood?"

Colin: "It made sparklers that caught the people on fire."

Me: "Sparks...make sparks that caught the people on fire, yes."

Colin: "So, they had to make long chimneys at the top so that wouldn't happen anymore."

Me: "Yes, that's right.  And, when the engine tracks, trains, and people came West, what people did they run off of the land?"

Cameron: "Navy* Americans."

*Also know as Native