Final answer:
The disagreements between different versions of a tax bill in the House and Senate are resolved by the Joint Conference Committee.
Step-by-step explanation:
When the House and Senate versions of a tax bill are not in agreement, the disagreements are resolved by the Joint Conference Committee. A conference committee is used to reconcile different bills passed in both the House and the Senate. These committees are appointed on an ad hoc basis and are necessary when a bill passes the House and Senate in different forms. Their role is critical in ensuring that both chambers pass identical bills as required by the Constitution. The disagreements between different versions of a tax bill in the House and Senate are resolved by the Joint Conference Committee.