Answer:
I do not think that it is the most reliable way to gain information since it is very hard to do and can be easily messed up. No, I don't think you can charge someone on only evidence from blood spatter, but if there was additional evidence I think that this would definitely help with the case but not on its own, since it doesn’t give you physical evidence about the suspect.
Explanation:
'N' is labelled 'runoff'. That's when the water is down. Streets are wet, worms come out of the ground, and water flows down the street to the sewer.
Given :
The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12.
To Find :
How many grains are there in the ball?
Solution :
Volume of ball of the ballpoint is :

Now, grain size of 12 has about 520000 grains/mm³.
Therefore, number of grains are :
