One of the advantages of dividing the project into stages, as advocated by PRINCE2, is that detailed plans can be prepared closer to the time events will take place. This allows planning to be based on more accurate, up-to-date information, improving the relevance and accuracy of the plans. This approach also allows for better response to changes and risks, as planning for later stages can adjust based on the outcomes and learnings from earlier stages.
PRINCE2 Foundation Manual

Reference http://prince2.wiki/Define_roles_and_responsibilities

In PRINCE2, the supplier is responsible for providing the resources necessary for delivering the project outputs. This includes supplying the skills, materials, and technologies required to produce the products of the project, ensuring that these resources meet the project's specifications and quality requirements.
References: PRINCE2 7 Foundation Handbook and official training materials.

Explanation/Reference:
Reference http://prince2.wiki/Initiating_a_Project#Objective