Answer:
1, 2 and 3
Explanation:
The most dense substance will settle at the bottom of the cup
It's the angle made by the incident ray when it's perpendicular to the surface. (Perpendicular lines are the lines that form a graph or like a 90-degree angle)
Change in state(from liquid to solid) and change in colour I believe.
2 is B. 3 is D. 4 is C. I think 5 is A. 6 is A. 7 is D. I think you are all correct. Good Luck!