The answer is A. Permeability.
Filtration can be used to separate an insoluble solid from a liquid, or a precipitate from the reaction mixture in which it formed. The solid which collects in the filter paper<span> is called the residue. The clear liquid which passes through the </span>filter paper<span> is called the filtrate.</span>
The average atomic mass if the element above is calculated by the sum of the product of the isotope abundance and its atomic mass unit. It is expressed as:
Average atomic mass = Σ xi(Mi)
<span>Average atomic mass = (.7547 x 248.7) + (.2453 x 249.4) = 248.87
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Hope this helps.