Q: Channel proteins and carrier proteins help substances diffuse across what?


Read this paragraph and choose the correct option from the provided answers:

Facilitated Diffusion Across a Cell Membrane. Channel proteins and carrier proteins help substances diffuse across a cell membrane. In this diagram, the channel and carrier proteins are helping substances move into the cell (from the extracellular space to the intracellular space).

 Choices:

- endoplasmic reticulum

- ribosomes

- cytoplasm

- cell membrane


A:
cell membrane