It's a bit of a tricky question because the term "mass structure" isn't a standard term in engineering or construction. Let's break down why a basketball isn't built like a traditional building, and what makes it work as a sphere:

* Function: A basketball needs to be lightweight, bouncy, and have a consistent shape for dribbling and shooting. This is completely different from a building's purpose of providing structural support and stability.

* Materials: A basketball uses a rubber bladder and a stitched leather or synthetic cover. This combination provides flexibility and resilience, but it's not strong enough to bear the weight of a building or withstand the stresses of a complex structure.

* Shape: Buildings need to be stable and upright, while a basketball needs to be a sphere. A sphere is not inherently strong for bearing weight, but it's perfect for bouncing and rolling.

* Internal Structure: A basketball has a hollow interior with an inflated bladder. This is crucial for its bounce, while buildings rely on internal supports like beams and columns for strength.

Instead of a "mass structure," a basketball relies on:

* Inflated Pressure: The air pressure inside the bladder provides its shape and bounce.

* Material Flexibility: The rubber and leather allow the ball to deform under impact, then return to its shape.

* Stitching and Seams: These reinforce the structure of the cover and provide a consistent surface.

In short, a basketball is not built like a building because it has different needs and functions. It relies on flexible materials, internal pressure, and a spherical shape to achieve its goals.