Answer:
a. 1.6×10^9
Step-by-step explanation:
The blood volume flowing per second is the same in each vessel, so we have ...
[tex]r_1^2v_1=n\cdot r_2^2v_2\\\\1^2\cdot 40=n\cdot (5\times 10^{-4})^2\cdot 0.1\\\\\dfrac{40}{2.5\times 10^{-8}}=n=1.6\times 10^9[/tex]
There are about 1.6×10^9 capillaries.