Stomata. Abscisic acud is releases in exrreme conditions when water conservation is more important that water loss amd so stomatal pore closes when ABA gets attached to receptors on membrane of guard cells
Burning wood, it is a chemical reaction and the only option that actually changes the composition of the substance. The burnt would cannot change back into normal wood now
Plants need to be water frequently basis because they will stop growing and the leaves/flower will die slowly and they will be a brown color,
