**How many cells do you have?**

The average eukaryotic cell is about **100 μm** (100 x 10^{-6} m. = 10^{-4} m.) long.

Your body has 100 trillion (10^{14}) cells (p. 15).

Total length of your cells lined up end-to-end:
(10^{14}) x (10^{-4} m.) = 10^{10} m. = 10^{7} km.

The earth's circumference is 40 million m. (40 x 10^{6} m. = 4 x 10^{7} m. = 4 x 10^{4} km.

10^{7} km. / 4 x 10^{4} km. = 250: your cells can wrap around the earth **250** times.