For a species to be classed as vulnerable, its population by more than 30 percent over the last three generations or 10 years. The problem is that when such a stipulation is applied to koalas, the Victorian boom offsets the Queensland bust, and the species stays off the list.
This has repercussions because northern koalas are different to southern ones. They are smaller, for example, and they contain a genetic variation not represented in the South. , a split listing has been devised koalas from New South Wales, the ACT and Queensland are now officially 'Vulnerable'; those from Victoria and South Australia are not considered threatened.
Result:
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Correct answer: While
Explanation: The word 'While' introduces a contrast between the koala's situation in different regions, fitting grammatically and contextually as it sets up a comparison between the troubled areas and those where populations are stable.
Meaning: 'While' means 'although' or 'whereas,' indicating that despite the koala's troubles in some areas, the situation is different in others.
Wrong options:
- Because: 'Because' indicates a reason, which does not fit the contrasting context of the sentence.
- However: 'However' suggests a contradiction but does not serve as a conjunction to introduce the clause effectively in this context.
- Despite: 'Despite' indicates a concession but does not grammatically connect the two clauses as needed.
Correct answer: are falling
Explanation: The phrase 'are falling' is in the present continuous tense, which is appropriate here as it describes an ongoing situation regarding koala populations in certain regions, aligning with the context of current population trends.
Meaning: 'Are falling' means that the koala populations are currently decreasing in number.
Wrong options:
- had been falling: This past perfect continuous tense implies a completed action in the past, which does not fit the ongoing context of the sentence.
- were falling: This simple past tense suggests a completed action, which does not accurately reflect the current situation being described.
- had fallen: This past perfect tense indicates a completed action before another past event, which is not suitable for the present context.
Correct answer: must have decreased
Explanation: The phrase 'must have decreased' indicates a necessary condition for a species to be classified as vulnerable, fitting grammatically as it expresses a requirement in the present perfect modal form, which is appropriate for discussing population criteria.
Meaning: 'Must have decreased' means that it is essential for the population to have reduced by a specific percentage over a defined time period.
Wrong options:
- will be decreasing: This future tense does not fit as it implies an action that has not yet occurred, rather than a requirement based on past data.
- was decreased: This passive voice construction is incorrect as it suggests an action was done to the population, which does not align with the context of discussing population criteria.
- has decreased: This present perfect tense suggests a completed action without the necessary condition implied, which does not fit the requirement being discussed.
Correct answer: For this reason
Explanation: The phrase 'For this reason' logically connects the previous information about the differences between northern and southern koalas to the conclusion about the split listing, fitting grammatically and contextually as it indicates causation.
Meaning: 'For this reason' means that the following statement is a consequence of the previously mentioned facts.
Wrong options:
- According to this: This phrase suggests a citation or reference, which does not appropriately connect the cause and effect relationship in this context.
- For instance: This phrase introduces an example, which does not fit as the following statement is not an example but a conclusion based on prior information.
- In contrast: This phrase indicates a comparison, which does not align with the causal relationship being established in the sentence.
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