Question

moving with the concentration gradient means... moving through a semipermeable membrane. movement of molecules that requires spending energy. movement of molecules from an area of lower concentration to an area of higher concentration. movement of molecules from an area of higher concentration to an area of lower concentration.

Explanation:

When molecules move with the concentration gradient, it means they move from an area where there are more of them (higher concentration) to an area where there are fewer (lower concentration). This is a natural process that doesn't require energy input. Moving through a semi - permeable membrane is a characteristic of some types of transport (like osmosis for water), but it's not the definition of moving with the gradient. Movement that requires energy is against the gradient (active transport). Movement from lower to higher concentration is also against the gradient.

Answer:

movement of molecules from an area of higher concentration to an area of lower concentration.