AP BIOLOGY

Detailed explanation-1: -During active transport, substances move against the concentration gradient, from an area of low concentration to an area of high concentration.

Detailed explanation-2: -Symporter. A symporter uses the downhill movement of one solute species from high to low concentration to move another molecule uphill from low concentration to high concentration (against its concentration gradient). Both molecules are transported in the same direction.

Detailed explanation-3: -Osmosis is the diffusion of water molecules across a semipermeable membrane from an area of lower concentration solution (i.e., higher concentration of water) to an area of higher concentration solution (i.e., lower concentration of water). Water moves into and out of cells by osmosis.