Answer:One well-known online petition platform is Change.org. It allows individuals and organizations to create and sign petitions advocating for various social, political, and environmental issues. The platform contributes to social change by raising awareness, mobilizing public support, and pressuring decision-makers to take action. By gathering thousands or even millions of signatures, petitions can influence policies, spark discussions, and bring about real change.Example of a Successful Petition:One of the most notable successes on Change.org was the petition to "Justice for George Floyd." This petition called for the arrest and prosecution of the police officers involved in Floyd's death in 2020. It became one of the most-signed petitions in the platform's history, gathering over 19 million signatures. The overwhelming public support contributed to the prosecution of the officers and helped fuel the global Black Lives Matter movement, leading to police reform discussions and legislative changes in various parts of the world.