On the basis of the above passage, the following assumptions have been made: 1. Global warming is a frequently occurring natural phenomenon. 2. The impending global warming will not adversely affect small mammals. 3. Humans are responsible for the loss of the Earth’s natural resilience. Which of the above assumptions is/are valid?

Passage

A research team examined a long-term owl roost. Owls prey on small mammals and the excreted remains of those meals that accumulated over time provide us an insight into the composition and structure of small mammals over the past millennia. The research suggested that when the Earth went through a period of rapid warming about 13,000 years ago, the small mammal community was stable and resilient. But, from the last quarter of the nineteenth century, human-made changes to the environment had caused an enormous drop in biomass and energy flow. This dramatic decline in energy flow means modern ecosystems are not adapting as easily as they did in the past.

QUESTION

CSAT

Easy

Comprehension

Prelims 2019

On the basis of the above passage, the following assumptions have been made:

Global warming is a frequently occurring natural phenomenon.
The impending global warming will not adversely affect small mammals.
Humans are responsible for the loss of the Earth’s natural resilience.

Which of the above assumptions is/are valid?

Select an option to attempt

Explanation

Statement 1 is incorrect. The passage mentions that about 13,000 years ago, the Earth went through a period of rapid warming, suggesting that global warming has occurred in the past. However, it does not specify how frequently this warming occurs. Therefore, we cannot infer from the passage that global warming is a "frequently occurring natural phenomenon." This assumption is not valid based on the information provided.

Statement 2 is incorrect. The passage describes how the small mammal community was stable and resilient during a period of rapid warming 13,000 years ago. However, it also states that human-made changes to the environment have caused a drop in biomass and energy flow since the last quarter of the 19th century, making it harder for modern ecosystems to adapt. While the past warming didn’t negatively affect small mammals, the passage suggests that modern environmental changes, including those related to human impact, may affect ecosystems negatively. This makes it difficult to infer that impending global warming would not harm small mammals. Therefore, this assumption is not valid.

Statement 3 is correct. The passage specifically mentions that human-made changes to the environment since the late 19th century have caused a dramatic decline in biomass and energy flow, which has made modern ecosystems less adaptive. This supports the assumption that humans are responsible for the loss of resilience in ecosystems. Therefore, this assumption is valid.

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