Those that rely on another to work. Every dependent is a place a change reaches further than intended.
Latin dependere (to hang from), from de- (down, from) + pendere (to hang); those that hang from, and so rely on, another thing to work.
Latin pendere is to hang, and a dependent is still hanging in that literal sense, suspended from something else's continued standing. Move what it hangs from, even slightly, and the motion travels all the way down.