If you were to make your own measurements, your significant digits should include all of the measurable digits (the digits that correspond to the marks on the ruler) as well as one estimated position beyond the smallest measureable digit (the 5 in 3.5 cm, and the 2 in 3.52 cm).
Step-by-step explanation:
It sucks that points have to be used in order to post questions.
Openstudy - the company that merged into Brainly - was much better.
Anyway, I think that the answer to this question is A. I'm not sure, though.
There are two variables here, which are time (minutes) and the number of beats, and they both have a relationship (68 beats in one minute), therefore it is an example of a unit rate
