15. The movement of molecules in a fluid or gas from a region of higher concentration to a region of lower concentration is called:

Explanation:

in gases it is called diffusion:)

c: warm water flows from the western tropical pacific toward south america. that should be the right answer! hope it .

ionic bonds are two oppositely charged ions that attract. a sodium ion has a 1 positive charge; a chloride ion has a 1 negative charge. sodium and chloride have oppostive charged ions that attract which forms an ionic bond. a chemical bond formed when two atoms share electrons is called