Final answer:
The phrase "where once you left your barefoot trace" prompts the listener to think about the passage of time and the lasting impact of human presence.
Step-by-step explanation:
The phrase "where once you left your barefoot trace" in line 4 prompts the listener to think about the passage of time and the fleeting nature of human presence. It suggests that even though the person who left their trace is no longer there, their memory lingers. The use of the word "barefoot" evokes a sense of innocence and vulnerability, emphasizing the impact and significance of their presence.