I believe you're looking for the word "use".
I know that seems overly simple, but I've been in construction for almost 40 years and the designation of a buildings purpose, residential, commercial, retail, office etc. is called its "use"
They are purposeless structures
I assume you are referring to structures that are left over and serve no apparent purpose. These are called vestigial structures.
NUCLEUS
pulpwood is mainly used for building houses other similar structures
Some plants have flowers to attract pollinators like bees and butterflies. The purpose of these floral structures is to facilitate the process of pollination, which is essential for the plant's reproduction and the production of seeds.
The purpose of radical neck dissection is to remove lymph nodes and other structures in the head and neck that are likely or proven to be malignant.
These structures are called vestigial structures. They are remnants of ancestral features that no longer serve a clear purpose in the organism's current form. Examples include the human appendix and whale leg bones.
Organizations need structures for purpose of administration and management. The consequences of not having well-set structures in organizations are quite severe and include mismanagements of funds, failure to achieve set goals and objectives and much more.
Yes, there are structures all around the world that vary in size, purpose, and style. These structures include buildings, bridges, monuments, and more, each reflecting the culture, history, and creativity of the people who built them.
The skeletal structures are made of an aluminum or steel alloy and its main purpose is to provide support to any new building during construction.
Plants need their leaves to gather sunlight for the purpose of photosynthesis.
In animals, structures such as antlers in deer and horns in cattle serve a similar purpose to implants by providing support for physical traits that enhance survival and reproduction. These structures are often used in mating displays or in combat for dominance. Additionally, beaks in birds and shells in mollusks function as protective adaptations that also aid in feeding. All these structures contribute to the animals' fitness in their respective environments.