Here's why:
* Conjunction: It connects two clauses or sentences.
* Adverbial: It modifies the entire clause or sentence it introduces, indicating a continuation of the previous thought and adding additional information.
Examples:
* "The weather was terrible. Furthermore, the traffic was a nightmare."
* "The team played well. Furthermore, they managed to score the winning goal in the last minute."
Let me know if you have any other questions!