Comparative investigation is a research method that makes comparison across different countries of the world. Limitation : data set in different countries may be defined differently. Benefit : the method is flexible.
The answer is mass. I have to comment more than 20 characters.
Pure water.
A salt solution contains impurities whereas pure water will not contain any impurities.
Impurities increase the boiling point (freezing point) of a substance.
Thus, I would expect the pure water solution to freeze faster than the salt solution.
V=IR therefore I=V/R=10/50=0.2A therefore the current is 0.2 A
