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

Influence on  decision-making power

Explanation:

The political parties in the congress are constantly fighting each to other for the achievement of their convictions through the vote, in this order of ideas the decision-making power would depend of the quantity of senators per political party, if there are many senator in an specific party the election process will be influence in a mayor measure  by those votes.

answer; i believe the correct answer is (general);