1define system, give one example of system and mention its 3 comonents 2-give one example of negative feedback
3-give one example of positive feedback
4-explain 4 spheres in earth

True or false 5. carrier proteins have the ability to to change shape and physicially move molecules across the cell membrane. 6. in a facilitated diffusion, the concentration of the molecules to be moved across the cell membrane is higher inside the the cell.