Final answer:
The department's unique mission is to focus on urban planning and design, not building tall skyscrapers or natural sciences.
Step-by-step explanation:
The unique mission of the department of Planning, Policy, and Design is to focus on urban planning and design. Their mission is not to build tall skyscrapers or to focus on natural sciences.
Urban planning and design involve creating and developing plans and policies for the use of land and the design of cities or towns. It includes considering factors such as transportation, housing, public spaces, and the environment to create sustainable and functional communities. Architects play a crucial role in this process by designing buildings and structures that support the activities and needs of the community.