Answer: The topic sentence is number 1 and the sentence that does not develop the main idea is number 9.
Explanation: The topic sentence of a paragraph is the sentence that expresses the main idea of that paragraph. In the given passage from "Lou Gehrig, An American Hero" by Paul Gallico, the topic sentences is "Lou Gehrig had unusual courage despite serious physical handicaps." The sentences that develop the main idea are those that complement the topic sentence, the one sentence that doesn't apport anything about the main idea is "It rained about three times a week."
