Answer:
detectives, police officers and occasionaly lawyers/attorneys.
Explanation:
Non essential officers, judges, district attorney investigators, federal agents, victums, witnesses and politics are not permited to enter crime scenes unless they can provide information and history about the event.
The density of gasoline is 0.7 g/cm3, and the density of water is 1 g/cm3. Thus the mass of the gasoline is 55*0.7 = 38.5g and the mass of the water is 60g.
Combining the 55 cm3 and 60 cm3 of substances with the aforementioned masses yields a volume of 55+60 = 115cm3 and a mass of 38.5+60 = 98.5g. The density is therefore 98.5/115 = 0.86 g/m3.
I believe the answer is an ion.