What results from reducing a substance to absolute zero?

Reducing a substance to absolute zero, which is 0 Kelvin or -273.15 degrees Celsius, theoretically results in the cessation of all molecular motion. At this extreme temperature, the kinetic energy of the molecules approaches zero, meaning that they are in their lowest energy state possible. This state corresponds to minimal movement, reflecting the idea that temperature is a measure of the average kinetic energy of particles. As temperature decreases, the motion of the particles becomes increasingly limited until, at absolute zero, molecular motion stops.

In the context of the other options, while the formation of new states of matter can occur at extremely low temperatures (such as Bose-Einstein condensates), this phenomenon does not directly imply behavior at absolute zero. Increased density might occur due to cooling, but it is not the primary result of reaching absolute zero itself. The claim that the system gains energy is fundamentally inaccurate, as reaching absolute zero means stripping away energy until it is at a minimum. The correct understanding is that at absolute zero, molecular motion ceases entirely, representing a theoretical limit of temperature where thermal energy is fully removed from the system.