Sam said, “Now I get a turn! Let’s read my dinosaur book!”
The prepositional phrase is "in" since it describes where the prairie dogs live which is "in New Mexico".
Intrinsic motivation is a motivation "from inside", with internal, rather than external awards.
Three of the things you mentioned have an external reward: the 500 Dollar prize( first option), the credit (third) and the hope of winning a blue ribbon (the last).
Only the second one has an intrinsic motivation: that you will be happy about performing this song (feeling proud of yourself, etc).
The reoccurring alternation of strong and weak sounds is rhythm.