The statement that best explains this result is: "When the gases are heated, they expand and become less dense than the surrounding gases, causing them to rise to the top of the container."
The rise of the mixture of gases to the top of its container can be explained by the principle of buoyancy. When a gas is heated, it expands and becomes less dense than its surroundings. As a result, this less dense gas will rise upward to occupy the higher available space and displace the denser gas. This phenomenon is known as convection and is the reason why heated gas rises to the top of its container.
