In general, life needs to maintain a pH level between
01-4
5-8
9-14

5-8

Explanation:

To answer the question we need to know that;

A pH of 1-6 is said to be acid with 1-3 being strongly acidic, while a pH of 8 to 14 is said to be basic with 12-14 being strongly acidic.Many living organisms or life systems tend to operate at a neutral pH. Neutral pH is the pH of 7 or close to 7.In this case, the pH of between 5 and 8 is fairly neutral.Extreme pH such as very acidic pH and very basic pH would be hostile to body systems of most living organisms.Therefore, life needs to maintain an almost neutral pH of 5 to 8.

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab.