A loosely organized group of people who ordinarily have little power but challenge the state power -- usually through disruption and sometimes violently.

The object of a social movement is usually an emotional issue, which may range from a very local question such as the location of a new highway all the way up to the constitution or identity of the state.

Aspects of the Political Situation that offer a social movement (or for that mater, any political group or entrepreneur) advantages and openings.

Examples could be the presence of potential allies, the absence of any other political movement in a niche, a breakdown of confidence in an incumbent leader, etc.

The executive portion of a parliamentary government. It consists of ministers, most of whom are usually members of the parliament.

Each minister is responsible for the administration of some part of the government's services, such as health or defense.

The cabinet leads the parliament, proposing legislation, conducting the country's foreign policy, and so on.  It serves at the pleasure of the parliament and can be ousted by a majority vote of no confidence.