Gravity modes, or g-modes, are oscillations in a star that occur due to the buoyancy force acting on fluid elements within the star. These modes are generated when regions of the star become unstable, causing them to rise and fall, similar to how a buoy moves in water. The restoring force is provided by gravity, which tries to return the displaced fluid to its original position. These oscillations can provide valuable information about a star's internal structure and dynamics. By studying g-modes, astronomers can gain insights into the star's composition, temperature, and evolutionary state, enhancing our understanding of stellar evolution and behavior.