th cell membrane or cell wall =D
Diffusion keeps the amounts of molecules inside and outside the cell in balance, or in a state of homeostasis.
Diffusion keeps the amounts of molecules inside and outside the cell in balance, or in a state of homeostasis.
Diffusion keeps the amounts of molecules inside and outside the cell in balance, or in a state of homeostasis.
Diffusion keeps the amounts of molecules inside and outside the cell in balance, or in a state of homeostasis.
Diffusion keeps the amounts of molecules inside and outside the cell in balance, or in a state of homeostasis.
The fuselage keeps the inside in and the outside out.
Diffusion keeps the amounts of molecules inside and outside the cell in balance, or in a state of homeostasis.
Diffusion keeps the amounts of molecules inside and outside the cell in balance, or in a state of homeostasis.
Diffusion keeps the amounts of molecules inside and outside the cell in balance, or in a state of homeostasis.
Diffusion keeps the amounts of molecules inside and outside the cell in balance, or in a state of homeostasis.
Skin, amongst other things, keeps what's meant to be inside, inside, and keeps what's meant to be outside, outside.
Dark matter is all around us, inside and out, is what holds the forces of gravity together, keeps it from flying apart.