Amajor problem caused by humans is the contamination and depletion of resources. a. solar b. water c. wind

B. Water

Explanation:

Solar, water and wind are the renewable resources. They are abundantly available in nature and are replenishable. Due to human intervention the most affected resource is water. As water is required for various activities by human society. With the use in large scale such a resource is also contaminated by humans due to sewage discharge in water bodies, industrial discharge, disposal of wastes and even the cremation of humans a ritual practice is performed in water bodies. This will likely to deplete the available freshwater for future.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.