To learn from a virtual body, it would need to be able to accurately simulate or predict how the body responds to internal and external changes.
Friction is a force that resists sliding motion between contacting surfaces. A bike, for example, has many instances of friction.
Water scarcity is essentially when there’s not enough water in the right place at the right time. Even in places that seem water-rich, it may not be clean enough for its intended purposes.
3D printing is the process by which we make a piece layer by layer, and the various forms of 3D printing differ in how they make each layer. Extrusion-based printing, or fused deposition modeling, uses filaments. It takes a raw material and extrudes it through a die to create a long strand That’s what a filament is.
Robots can be similar to people, but they aren’t necessarily so. People create the robots and can choose what aspects of functionality and design are important, but there are some benefits you get out of similarity.