AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
The practice is called defection. Under the anti-defection law, an MLA or MP who changes parties loses their seat in the legislature.
Source: How can parties be reformed?, Chapter 4
The question tests two things: the term for switching parties and the legal consequence. The source explicitly states the law was passed to prevent defection, and the penalty is losing the legislative seat. Both parts must be included in one line to score full marks.