Which of these cell junctions form a barrier to the passage of materials? keratin fibers tight junctions desmosomes (anchoring junctions) gap (communicating) junctions plasmodesmata.

tight junctions

Explanation:

Cell junctions are types of connections that allow cells to communicate and may or may not allow exchange of materials. The tight junctions prevent the passage of molecules and ions to pass between spaces in cells. They also help in maintaing the polarity of cells by preventing diffusion of integral proteins. In addition, they can function to hold cells together firmly.

prism b but im not for sure

the electromagnetic energy from the sun arrives in the form of visible and invisible light.