This is part of a series of TOEFL Reading Question Types. In today’s post, we will discuss a "Rhetorical Purpose" question. In a "Rhetorical Purpose" question, you will see the question phrased like the following:
Why does the author mention that “...” in paragraph 5?
This type of question requires you to understand why the author has included pieces of information. The answer is not directly stated in the reading passage. To solve this type of question, you need to understand the main point of the paragraph and how the referenced information(Usually a sentence) is related to the main point of the paragraph.
In this type of question, you will see answers that contain phrases like the following
- to support
- to explain
- to compare
- to question
- to show
- to account for
- to illustrate
- to refute
- to note
- to criticize
- to contrast
Let’s see an example of a rhetorical purpose question.
 Darwin's theory is that 'selective breeding' occurs in nature as 'natural selection' is the engine behind evolution. Thus, the theory provides an excellent basis for understanding how organisms change over time. Nevertheless, it is just a theory and elusively difficult to prove. One of the major holes in Darwin's theory revolves around “irreducibly complex systems.” An irreducibly complex system is known as a system where many different parts must all operate together. As a result, in the absence of one, the system as a whole collapses. Consequently, as modern technology improves, science can identify these “irreducibly complex systems” even at microscopic levels. These complex systems, if so inter-reliant, would be resistant to Darwin's supposition of how evolution occurs. As Darwin himself admitted, “To suppose that the eye with all its inimitable contrivances for adjusting the focus for different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I free confess, absurd in the highest degree.
Question : In paragraph 4, what was the author's purpose of including a quote that the belief that the complexity of the human eye could have been formed by natural selection seems highly unlikely?
A. To provide evidence that irreducibly complex systems exists
B. The prove that the natural selection contradicts the basis of Darwin
C. The support that the natural selection contributes to the basis of Darwin
D. The support the claim that natural selection is just a theory and difficult to prove
The answer is D.
D is the correct answer. The quote shows that even Darwin, who created the theory, acknowledges that some of the occurrences are difficult to believe and difficult to prove. A is incorrect because the quote is not providing information that would prove the existence of irreducibly complex systems. B and C are incorrect because the quote does not say whether the idea of natural selection contributes to or contradicts the theory.