Oxygen is a pure substance, as it is composed of only a single kind of atom. Which is the oxygen atom, it cannot be broken or degraded down any further into constituents that make up the element. In terms of both chemically and physically.
Answer:
The correct option is A
Explanation:
Water from a river is used for many activities in a community. These activities could include (but not limited to) tourism, drinking for animals, local transport, irrigation for nearby farming, recreation (as in swimming), habitat for some living organisms among others. Rivers are not limited by what limits the influence of oceans such as taste (it's saltiness, which cannot be used in farming also) and wave current.