Which statement correctly describes the bars on a bar graph representing the data?

The right answer is C.

A bar chart, also known as bar graph or column diagram, is a way to graphically represent a set of data or values, and is made up of rectangular bars of lengths proportional to the values represented. Bar graphs are used to compare two or more values. The bars can be oriented horizontally or vertically.

Since the value obtained at very low concentration (30) is twice the value obtained at average concentration (15), it can be deduced that "C" is a correct answer. The other answers are false.

the answer is; comparing the frequency of collisions with and without the device

this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.