Type of change that doesn't involve the formation of a new kind of matter

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

If you want to create an electrical current, which situation would produce a solution capable of this

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange