Completar frases Active & Passive TransportVersión en línea The students need to find out the sort of tense according to the blank space por ErikBass 1 allows disposal has of called made called surrounded get is has to thrive addition has In to rid All living things are up of tiny units cells . The cells are by a covering a membrane . The membrane controls what moves in and out of the cell . Cells need many kinds of materials in order to . They must have water , oxygen , glucose ( sugar ) , sodium , potassium and a variety of other minerals . The body to have a delivery system to get these materials where they need to go . , every cell produces waste materials that it needs . The body to have a method of waste collection and . Like a fl eet of trucks form a transport system to the pick up and deliver goods in the world , the body a transport system , too . There are two types of transport : active transport , and passive transport . Passive transport is easiest for the cells because they don't need to use any energy to make it happen . Diffusion the simplest and most common form of passive transport . During the diffusion process , tiny particles of the materials that need to be delivered to the cells are spread through either a gas , like oxygen , or a liquid , like water . Areas with high concentrations of the materials slowly diffuse them to areas of low concentration of the materials . Osmosis is a unique form of passive transport that water pass through the cell membrane but keeps most other materials out .
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