Part A is 2.5 x [tex]10^{-5} [/tex] because the decimal place has been moved five times to the left, which makes it negative.
Part B is
First, find what the diameters of both things are written out.
1 x [tex]10^{-5} [/tex] = .00001
1 x [tex]10^{-4} [/tex] = .0001
Now find out how many times the size of a cell has to be multiplied to equal the diameter of a grain of sand.
.00001 x 10 = .0001
.0001 = 1 x [tex]10^{-5} [/tex]
So the diameter of a grain of sand is 10 times longer than the diameter of the average cell in the human body.
