Answer
part b (2 points): how many times longer is the diameter of a grain of sand than the diameter of the average cell in the human body? show your work.

Diameter of a grain of sand = 2 x 10^{-4} 

Diameter of the average cell in the human body = 1 x 10^{-5}

Difference of diameter of grain of sand and cell of human body

= 2 x 10^{-4} - 1 x 10^{-5}

= 

= 

= 

= 

= 

= 19 × 10^{-5}

Hence, the diameter of a grain of sand is 19 × 10^{-5} longer than the diameter of the average cell of the human body.

Ithink if im not mistaking b is -3 but im not a 100% sude