Active transport requires energy for the movement of molecules whereas passive transport does not require energy for the movement of molecules. In active transport, the molecules move against the concentration gradient whereas, in passive transport, the molecules move along the concentration gradient.
The correct formula for population growth is the individuals added to the population via birth or immigration, minus the individuals removed from the population via death or emmigration. Therefore the answer is (B+I)-(D+E), or B+I-D-E
