28. What is the crucial role of ATP in active transport? (A) ATP hydrolysis provides the energy required to move substances against their concentration gradient. (B) ATP provides the energy required to move substances down their concentration gradient. (C) ATP acts as a structural component of transport proteins, facilitating their movement within the membrane. (D) ATP binds directly to the transported substance, altering its chemical properties to facilitate its passage across the membrane. (E) ATP regulates the fluidity of the cell membrane, allowing for easier diffusion of substances.