Final answer:
Big Yellow Taxi's harmony is light-hearted and catchy, featuring an open-tuned guitar in a major key that contrasts with its environmental message.
Step-by-step explanation:
The song Big Yellow Taxi by Joni Mitchell features an overall harmony that is light-hearted and catchy, with clear influences from folk music traditions. The harmony supports the song's environmental and social themes, with a memorable jangle of open-tuned guitars that contribute to its distinctive sound. Lyrics lamenting the paving of paradise to put up a parking lot are underscored by a major key tonality, which adds a sense of irony to the song, contrasting the upbeat music with the serious message of environmental conservation.