Answer
Polarization of Congress is a measure of the overlap between two parties, where a high level political polarization will mean that the Republicans agree with fellow republicans and that democrats agree with democrats.
Party polarization occurs when the division between Democrats and the Republicans reach extreme differences in terms of beliefs and ideas of many political parties.
Step-by-step explanation
Party polarization is caused by : Voters who tend to cast votes to the candidate identifies by their party, hence if the winning candidate’s voters have same ideologies that are against the other party’s ideologies, the member of congress will make decisions on favor of the majority thus creating a division in congress similar to that existing between voters. In polarization of congress Gridlock is a common trend because reaching a compromise state is very tough.