LIFE SCIENCE

Detailed explanation-1: -Passive transport, most commonly by diffusion, occurs along a concentration gradient from high to low concentration. No energy is necessary for this mode of transport.

Detailed explanation-2: -Facilitated diffusion is a type of passive transport that uses specialized proteins, such as channel proteins and carrier proteins, to help molecules move across a cell membrane. In this process, molecules can move down their concentration gradient without requiring any energy input from the cell.

Detailed explanation-3: -Facilitated transport (or facilitated diffusion) is defined as a mediated transport not requiring energy expenditure, as exemplified by placental glucose transfer, which is mediated by facilitative glucose transporters expressed in the syncytiotrophoblast MVM and BM.