<prompt> Active method of transport is-Simple diffusionFacilitated diffusionAlong concentration gradientAgainst concentration gradient  <response>: Ans. is d i.e., Against concentration gradient Transport across a cell membrane is divided into passive or active, based on whether it is along the concentration gradient or against the concentration gradient.1 Passive transport It is in the direction of concentration gradient i.e., Downhill movement Does not require energy expenditure Example are : -i Without carriers : - Simple diffusion, osmosisii Through carrier: - Facilitated diffusion2 Active transport It is against the direction of concentration gradient, i.e., Uphill movement. Energy e.g., ATP is required Carrier protein is required Examples are primary active transport and secondary active transport. 