In what direction do substances move across channel proteins in terms of concentration)?

High to low concentration

Explanation:

The process of substances moving across the cell membrane through channel proteins represents a type of diffusion called facilitated diffusion. This type of diffusion does not require energy intake, and for this reason, substances involved in facilitated diffusion always move from areas of high concentration to areas of low concentration, because going the opposite direction would require ATP (energy).

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).

the answer is 1. photosynthesis. glad to