Incorrect: Organic vegetables are healthy.
Correct: Because the pesticide levels in organic vegetables are monitored so often, they are healthier compared to non-organic vegetables.
Explanation: This topic sentence tells you that organic vegetables and non-organic vegetables are being compared. It also argues that organic vegetables are healthier than non-organic vegetables.
"A topic sentence has several important functions: it substantiates or supports an essay's thesis statement, it unifies the content of a paragraph and directs the order of the sentences, and it advises the reader of the subject to be discussed and how the paragraph will discuss it" (Writing Tutorial Services).
