The Laysan Rail, an insectivore bird once present on several of the

Question

The Laysan Rail, an insectivore bird once present on several of the Hawaiian Islands, can no longer be found and is thought to be extinct. Scientists originally thought that a decrease in the amount of ground vegetation available for nesting was responsible for the decline of the bird. However, they now believe that increased competition for food was ultimately responsible for the Laysan Rail's inability to survive.

Which of the following would best help to account for the change in the accepted explanation for the Laysan Rail's extinction?

A. The vegetation on the Laysan Rail's home island was decimated when rabbits were introduced to the island in the 1910s.

B. When attempts were made to relocate the Laysan Rail to other islands, the birds lost the geographical cues that they relied on for finding mating sites.

C. The Laysan Rail builds nests under dense ground cover to protect the eggs.

D. An increase in the use of pesticides resulted in a decrease in the numbers of flies and moths present in the Laysan Rails territory.

E. Many species nested.in the same types of vegetation as the Laysan Rail.

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dhart · Answer

conclusion changed from scarcity of nesting requiremnts to prey requiremnts , the argument that suppports this conlcusion is that n increase in the use of pesticides resulted in a decrease in the numbers of flies and moths present in the Laysan Rails territory

harjas2222 · Answer

I believe the answer is D,

This is because B seems to be a trap, and would I deduce that option to be so? Well it adds a red herring, only able to explain the nesting situation while the new cause is unexplained, and Rabbits are Herbivores not Insectivores.

D fits

The increase in pesticides leading to direct decrease of insects for the bird seems to be the best fit.

Minka99 · Answer

I'll write the reasons why I eliminated answers first:
A) 1910s seems too specific, since the passage does not mention when the bird is believed to have gone extinct. The rabbit situation could have happened after, it is unclear.
B) Mating is not mentioned as one of the 2 potential reasons, so its out of scope
C) this doesn't really strengthen either or; it explains how the ground vegetation scenario but does not provide information to sway us in either direction 
E) this is completely irrelevant- we are only interested in the exact species

This leaves D as the correct answer in my mind:  An increase in the use of pesticides resulted in a decrease in the numbers of flies and moths present in the Laysan Rails territory.  This is the only answer choice that actually strengthens one by weakening the other

Vivek1707 · Answer

A. This explains why vegetation decreased, which supports the  old explanation , not why scientists changed their minds.
B. This explains why relocation attempts failed, but doesn't explain the original extinction.
C. This confirms that lack of ground vegetation could affect nesting, again supporting the  old theory .
D. Correct Pesticides reduced flies and moths, which are the Rail's food. So the bird may have faced  food scarcity , providing a reason to shift from the nesting-vegetation explanation to  competition for food .
E. Other species using the same vegetation could explain competition for nesting sites, not competition for foo

The Laysan Rail, an insectivore bird once present on several of the

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­The Laysan Rail, an insectivore bird once present on several of the

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615 to 715 in 15 Days (Ria's Strategies)

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The Laysan Rail, an insectivore bird once present on several of the