Which mechanism is analogous to a door that opens when the wind catches it?

The correct response relates closely to the concept of mechanical gating, which describes a mechanism that opens or closes in response to physical forces or environmental changes. Just as a door can swing open when a gust of wind pushes against it, mechanically-gated channels in cell membranes open in response to physical stimuli, such as stretch or pressure. This allows certain ions or molecules to flow through the channel, similar to how wind allows a door to move in the environment.

In contrast, options like active transport, passive transport, and facilitated diffusion involve other mechanisms that do not directly relate to physical forces in the same way. Active transport requires energy to move substances against their concentration gradient, while passive transport and facilitated diffusion rely on concentration gradients without the influence of direct physical forces. Thus, mechanical gating stands out as it precisely captures the analogy of a door responding to wind, emphasizing the role of physical triggers in channel function.