The concept expressed in (D) - that "recent scientific data and calculations support the claims that the earth's atmosphere is becoming warmer and that the greenhouse effect is a major case for this warming trend" - is the correctly identified main point of the passage.
The passage states that "evidence that the earth's atmosphere has warmed has become quite compelling..." (lines 1-2) and goes on to describe the scientific data supporting the claim that the earth's atmosphere is becoming warmer throughout the first paragraph.
Lines 11-13 state that "...other recent studies have strengthened the controversial link between this increase and the 'greenhouse effect.'" The passage then goes on in more detail to discuss scientific data regarding the impact of the greenhouse effect.
Moreover, the final sentence of the passage clearly reinforces the main idea as articulated in (D). It states, "In light of all this, it seems reasonable to conclude that changes in the earth's atmosphere have raised its equilibrium temperature, and that greenhouse gases represent the best explanation of that shift" (lines 55-59).
Does that make sense? Please let us know if you have any other questions!
christophergogoon June 7, 2022
Why not C?
Emil-Kunkinon June 13, 2022
Hi Christophergogo,
C is too narrow to be the main point. While C is correct, it essentially serves as a summary of the middle paragraph- while the idea that the degree of warming is true it is not the main point of the passage. C appears to be ambivalent about the idea that greenhouse gases cause global warming. To say something is "consistent with" a theory is not to say that X caused Y. D, like the passage, is much more commited to the idea that warming is caused by greenhouse gasses.
