Answer:
Fraction-of-occurrences of 115In isotope 
Explanation:
As we know weight of 113 In isotope is equal to the sum of product of fraction-of-occurrences of two constituents isotopes and their atomic weight
------(1)
As we know sum of fraction-of-occurrences of two constituents isotopes is equal to one.
---------(2)
Substituting the given values in equation 1, we get

Substituting this value in equation 2 we get -

All matter whether solid, liquid, gas has a chemical formula or elemental symbol.
Filtration may work, there are many types of filters capable of filtering specific types if compounds.
Answer:
People throw their trash and pollution into the fresh water and make it not as fresh or safe to the animals as much as it could be.
Explanation:
The biosphere. This is the layer that contains all life on the planet.