Does diffusion require proteins in the cell membrane

The simplest forms of transport across a membrane are passive. ... In cells, some molecules can move down their concentration gradients by crossing the lipid portion of the membrane directly, while others must pass through membrane proteins in a process called facilitated diffusion.

Hopes this helps :P

c. establishing proper sleep hygiene

a=c and then d= c because of the band so you get ac/dc and you add them together you get sound waves