Answer:
14 × 10^(-19) m
Explanation:
We are told that the diameter of the red blood cell is 7 × 10^(-6) m
And that number of red blood cells in the person is; 2 × 10^(-13) red blood cells
Since they are held end to end, the length of the line would be;
7 × 10^(-6) × 2 × 10^(-13) = 14 × 10^(-19) m