Answer:
Since boron only has two electron shells, it is about as capable of gaining electrons as it is of losing electrons, so it behaves as a metalloid. The other elements in this group have more electron shells, so it is much easier for them to lose their valence electrons and they behave like metals.
The original source of phosphorus in a terrestrial ecosystem is soil microorganisms. soil becomes deficient in phosphorous leading to ecosystem retrogression. phosphorous can be found in our body, it builds strong bones and teeth.
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Taxonomy is the classification of something, especially organisms.
So the answer is D. All living organisms