Oceans :unusable
Rivers :usable
Glaciers :usable
Freshwater: usable
Lakes :usable
Groundwater :usable
Because there is only one stable ionic compound made up of potassium and chlorine, and that is KCl. So calling is "mono chloride" or similar would be redundant assuming you understand basic chemistry (i.e. knowing oxidation numbers of K is +1 and Cl is -1). When compounds can exist in multiple forms in nature like CO and CO2 you will preferably indicate it through the nomenclature, calling one a monoxide and the other a dioxide.
Answer:
Equation 2, because K being more reactive, exchanges position with Pb in PbNO3.
Explanation:
Hello there!
In this case, according to the given reactions, it is possible to realize that according to the reactivity series, since K is is group 1A of alkali metals, we infer it is by far more reactive than magnesium, for that reason last two choices can be easily discarded. Now, considering equation 2, it would be necessary to complete it to figure out the correct option:

Whereas it can be seen that potassium exchanges position with Pb according to the double displacement reaction; therefore, the correct answer is "Equation 2, because K being more reactive, exchanges position with Pb in PbNO3".
Best regards!