The SI unit for mass is the kilogram. When massing a fish or any other substance for calculation the use of the kilogram unit will not require changing units as opposed to Imperial measurements.
Since the unit for mass in SI is kilogram (kg) then you should use this to measure the mass of a fish and any other product that has a mass.
Kilograms, unless it is a little fish - in which case, grams.
Meters, Centimeters, Millimeters
Grams, Kilograms
You might discover that solids have mass and they have volume.
The age of the material.
The two main factors in determining the average atomic mass of an element are:the isotopic composition of the element (the fraction of each isotope)the atomic mass of each isotope
Just adapt the formula for density to find the mass of an object. After adapting it, it should be like this: Volume*Density=Mass
Obtain the molecular mass by determining the m/z value of the molecular ion peak (rightmost in the spectrum).
A mass balance.
Grams for small fish, kilograms for larger fish.
The effect of gravity is measured.
You might discover that solids have mass and they have volume.
The atomic number.
Density = Mass/ Volume
The age of the material.
Density = Mass / Volume. So, to write it shorthand, you would write D = m / v.
The two main factors in determining the average atomic mass of an element are:the isotopic composition of the element (the fraction of each isotope)the atomic mass of each isotope
Look on a periodic table.
... mass.
Mass is a major factor.