Short answers, pulled from the story.
A political party is an organization that coordinates candidates to compete in elections and participate in governance. Its members commonly hold similar ideas about politics, and the party may promote specific ideological or policy goals while contesting elections under a shared label.
Modern political parties are considered to have emerged around the end of the 18th century, first appearing in Europe and the United States. Some scholars trace the first modern parties to early modern Britain in the 17th century after the Exclusion Crisis and the Glorious Revolution, and the Rockingham Whigs have been identified as the first modern political party.
Political scientists distinguish elite parties, mass parties, catch-all parties, cartel parties, and niche parties. Maurice Duverger first separated elite from mass parties, Otto Kirchheimer coined the catch-all party, and Richard Katz and Peter Mair developed the cartel party thesis describing parties as semi-state agencies.
Scholars give several explanations, including that parties arise from pre-existing social cleavages, that they align incentives for candidates and legislators across districts, and that they serve as a simplifying heuristic that lets voters make informed choices with less mental effort. Their ubiquity has led researchers to remark that the existence of political parties is almost a law of politics.
In a one-party system power is held entirely by one party, as with the Communist Party of Cuba. A two-party system has two parties with a realistic chance of governing, such as the Democratic and Republican parties in the United States. A multi-party system gives more than two parties a real chance of power and often produces coalition governments, as in India, Indonesia, Pakistan, and Brazil.
Political parties draw funds from dues-paying members, advocacy groups, corporations, trade unions, self-funding candidates, and government support. Of the 180 countries examined by the International Institute for Democracy and Electoral Assistance, nearly all have some form of public funding, and contemporary elections in the largest democracies typically cost billions or even tens of billions of dollars.
Parties adopt colours and symbols mainly to help voters identify, recognize, and remember them, which is especially important where much of the population may be illiterate. Associations can be inconsistent, and the United States is a notable exception where red represents the conservative Republican Party and blue the left-leaning Democratic Party.