#### Answer

Please see the work below.

#### Work Step by Step

We know that
The number of atoms in a cell can be determined as follows
$n=\frac{\frac{4}{3}\pi(\frac{D_{cell}}{2})^3}{\frac{4}{3}\pi(\frac{D_{atom}}{2})^3}$
$n=(\frac{D_{cell}}{D_{atom}})^3$
We plug in the known values to obtain:
$n=\frac{10\times 10^{-6}}{0.1\times 10^{-9}}^3=(10^5)^3=10^{15}$
Thus, we can conclude that the number of atoms in a cell and the number of cells in the body are almost same.