Answer:

Explanation:
We have to combine the following formula to find the mass yield:


The diffusion coefficient : 
The area : 
Time : 
ΔC: 
Δx: 
Now substitute the values

![M=-(6.0*10^{-8} m/s^{2})(0.25 m^{2})(3600 s/h)[(0.64-3.0kg/m^{3})(3.1*10^{-3}m)]](https://tex.z-dn.net/?f=M%3D-%286.0%2A10%5E%7B-8%7D%20m%2Fs%5E%7B2%7D%29%280.25%20m%5E%7B2%7D%29%283600%20s%2Fh%29%5B%280.64-3.0kg%2Fm%5E%7B3%7D%29%283.1%2A10%5E%7B-3%7Dm%29%5D)

Answer: drugs and rushing cars
Explanation: drug dealers are everywhere on city streets nowadays they have been killing young adults
rushing cars or reckless drivers cut curb fast and potentially someone can get hurt they are speeding and not worrying about other people lives at stake
I think option c 12 is currect