Final answer:
The most appropriate scale of measurement for measuring height and weight differences is the ratio scale.
Step-by-step explanation:
When measuring height and weight differences, the most appropriate scale of measurement is the ratio scale.
The ratio scale of measurement is the highest level of measurement, which has a definite ordering and a starting point. It allows for the calculation of ratios between values and meaningful interpretation of differences.
In the given scenario, height and weight are quantitative measurements that can be accurately represented and compared using the ratio scale.