New PMP Question & Answers with explanation

Robert has recently joined an automobile manufacturer. He now has a project that was already in the execution phase. Recently, one of the key stakeholders has raised serious concerns over the project’s scope. Robert now wants to review the previous project communications to understand how the current project scope was agreed to by all key stakeholders in the past. Where can he find this information?
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Which of the following techniques used in adaptive lifecycles helps in minimizing scope creep?
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Your project team is having a dispute with a vendor about whether a specific task is within the project’s scope. The scope statement does not provide implementation-level details that could resolve this dispute. There is no WBS, however, because the project sponsor insisted that the project be started right away without pausing to create standard project planning documentation. Who is at fault?
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Projects with adaptive life cycles use product backlogs to define a project’s scope. The product backlog is a set of:
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Due to the unexpected release of a similar product from a competitor, the Widgets International executive team has stepped up the pressure on the product team to release the Widget product three months earlier. The project manager uses what technique to shorten the schedule but maintain the project scope?
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