Question

How do political parties affect the structure or processes of Congress?

When members of Congress are equally divided by party, it is usually easier to pass bills.
If one party dominates Congress, it is much easier to pass bills that the party supports.
Congress allows only a certain number of members from each major political party.
The two houses of Congress are intentionally under the control of separate parties.

Answer 1

Answer:

If one party dominates Congress, it is much easier to pass bills that the party supports.

Explanation:

The legislative process is a complicated process of negotiation and bargaining. Parties try to push and discuss bills that are in accordance with their party's ideology, their constituency's needs or the demands of lobbyists.  

Since both parties have very different voters, backers, and ideologies, the negotiation can be bitter and it often is. Draggin the passing of bills. The more divided Congress is, the more difficult it becomes to pass a bill.