How it fits together
Congress is the legislative branch. The House represents congressional districts, with seats distributed among states by population. The Senate represents states equally: every state has two senators. This arrangement balances representation of people with equal representation of states.
A closer look
House members serve two-year terms; senators serve six-year terms. Senate elections are staggered, so roughly one-third of Senate seats come up every two years. For a bill to become law through the usual process, both chambers must agree to the same text before it goes to the president.