<Table> <Tr> <Td> </Td> <Td> This article includes a list of references, but its sources remain unclear because it has insufficient inline citations . Please help to improve this article by introducing more precise citations . (September 2016) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article includes a list of references, but its sources remain unclear because it has insufficient inline citations . Please help to improve this article by introducing more precise citations . (September 2016) (Learn how and when to remove this template message) </Td> </Tr> <P> Passive transport is a movement of ions and other atomic or molecular substances across cell membranes without need of energy input . Unlike active transport, it does not require an input of cellular energy because it is instead driven by the tendency of the system to grow in entropy . The rate of passive transport depends on the permeability of the cell membrane, which, in turn, depends on the organization and characteristics of the membrane lipids and proteins . The four main kinds of passive transport are simple diffusion, facilitated diffusion, filtration, and osmosis . </P>

Identify two types of transport across a plasma membrane