Short answers, pulled from the story.
William Dwight Whitney defined a building as having three core elements: a roof, walls, and permanent placement. He published this definition in 1901 within The Century dictionary.
Clear evidence of homebuilding exists from around 18,000 BC. Buildings became common during the Neolithic period when people lived in communal longhouses or pit-houses.
Paul Francis Wendt and Alan Robert Cerf stated that three stories or less generally defines a low-rise building. They published their analysis on real estate investment in 1979.
Vehicles such as trailers, caravans, ships, and passenger aircraft are treated as buildings for life safety purposes. Zoning ordinances apply regardless of intended use for these objects.
A real estate developer secures funding for any given project. Financial institutions or other investors provide necessary capital to support the development.