Can anyone please explain.I assure that I have given Powerprep test 2.

Explanation



The meaning of the sentence is that the birds, the species, are going to decline. As such, you need 3 words in this fashion.

This kind of specie of bird X is precarious in its amount, I.E they are in dangerous BUT at the same time lots of species are in the same situation, falling for years in numbers. So, the scientists are investigating this decline.

Hope this helps.
regards

I do not understand how they got "falling" for the second blank. Can someone help?

While the cerulean warbler's status may be particularly (i) __________ , it is just one of the many species of migrant birds whose numbers have been (ii) __________ for years. Increasingly, biologists investigating the causes of these (iii) __________ are focusing on habitat loss in the Tropics, where the birds spend the winter.

Actually, we do have a decrease in the numbers of these birds. These numbers falling is continuous over the years.

Now I hope this helps

regards

Blank 2 and blank 3 should be synonym. The hint is at the last part of the final sentence of the question

I'm sorry but I don't understand the first blank. "While" is the trigger word, so shouldn't secure be right word?

Yes, while is indicating contrast, but the trick here is that it is a contrast in degree as indicated by the adverb "particularly". So, while indicates that the bird is especially affected by the situation affecting all of the birds. Therefore, the first blank should be a term that is a greater degree of peril such as "precarious". Hope that helps!
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