When the House and Senate pass different versions of a bill the differences are resolved by a committee?

"All Legislative Powers herein granted shall be vested in a Congress of the United States, which shall consist of a Senate and House of Representatives."

(Article I, Section 1, of the United States Constitution)

How Are Laws Made?

Laws begin as ideas. First, a representative sponsors a bill. The bill is then assigned to a committee for study. If released by the committee, the bill is put on a calendar to be voted on, debated or amended. If the bill passes by simple majority (218 of 435), the bill moves to the Senate. In the Senate, the bill is assigned to another committee and, if released, debated and voted on. Again, a simple majority (51 of 100) passes the bill. Finally, a conference committee made of House and Senate members works out any differences between the House and Senate versions of the bill. The resulting bill returns to the House and Senate for final approval. The Government Printing Office prints the revised bill in a process called enrolling. The President has 10 days to sign or veto the enrolled bill.