which set of data would be best illustrated with a bar graph?
the effect of hours spent exercising on heart rate
the number of skyscrapers in 5 different cities
an illustration of how the humidity in the air responds to the temperature of the air
data showing how the number of hours spent studying affects the score on an exam

the number of skyscrapers in 5 different cities ( second choice)

the number of skyscrapers in 5 different cities

Explanation:

A bar graph is a perfect way to show the relation between two components where the components are not variable. Here if you look at second option, the two components are: No. of skyscraper and cities. It is evident that the skyscraper's no. is not a variable and will remain fixed.

While if you look at the other option, the components are variable and thus can not be represented on a bar graph.

protons in

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg