Weak acids such as carbonic or sulfuric acid react with rocks in the ground, such as limestone. Groundwater reacts with limestone and the dissolving of limestone takes place which forms karst features, such as caverns.
The answers, respectively, are:
resting potential; action potential.
I think the correct answer from the choices listed above is option D. Simple diffusion is the cell transport that allows small molecules to move from an area of higher concentration to an area of lower concentration without energy being <span>required from the cell.</span>