In the passage about western Kansas and the disappearance of the prairie, the author's argument is based primarily on which of the following?

Introduction / Context:
This question asks what mainly supports the author's argument in the passage about western Kansas. Although the passage includes some factual statements, the driving force behind the argument is the author's emotional reaction to the transformation of the prairie landscape.

Given Data / Assumptions:
• The author mentions feeling a pang of regret when thinking of the family history on the land.
• The land is described as torn up by agriculture and largely changed.
• The author recalls being moved and enthralled by the expanse of the prairie.
• Pride in the identity as a plains daughter is explicitly stated.

Concept / Approach:
To identify the basis of an argument, we look at what the author relies on most: personal emotions, historical records, numerical data, or inherited opinions. Here the narrative is clearly first person and introspective, emphasising feelings and perceptions rather than formal studies or ancestral reports.

Step-by-Step Solution:
Step 1: Note the frequent use of first person statements such as I experience, I have known and I have felt. Step 2: Observe the emotional vocabulary, including pang of regret, romantic quality and enthralled. Step 3: Check whether the passage presents any statistical data or formal historical research; it does not. Step 4: Confirm that the reflections come from the author's direct experience, not from ancestors. Step 5: Conclude that the argument rests primarily on feelings born out of personal experience.

Verification / Alternative check:
Ask which option would still make sense if we removed specific numbers but kept the author's emotions. The passages impact would remain strong because it is driven by internal reactions to the land, so feelings from personal experience must be the main basis.

Why Other Options Are Wrong:
Facts of history and statistical studies: No numerical or formal historical evidence is provided, only general statements about change.
Facts derived from personal observations: The author does observe the land, but the emphasis is less on factual reporting and more on emotional response, making feelings more appropriate than dry facts.
Feelings passed down by ancestors: The passage never says that the author inherited these feelings; they arise directly from personal encounters with the land.

Common Pitfalls:
Many students confuse personal observation with emotional experience. Here, while observation exists, the central thrust of the argument is clearly emotional, expressed through words of regret and pride rather than neutral description.

Final Answer:
The correct answer is feelings the author has picked up from personal experience, because the passage is driven by the author's own emotional response to the changing prairie landscape.