Answer:
They contain a main idea, a secondary thought, and a purpose that is stated in an introduction.
Step-by-step explanation:
Transitions are the words, phrases, or even sentences that are used to move from one point to another while still connect the ideas from one paragraph to another. They help in preventing the abrupt start of a new paragraph, allowing the readers to easily understand the move from one paragraph to the next.
Among the given options, the one statement that is not correct regarding paragraph transitions is that "[transitions] contain the main idea, a secondary thought, and a purpose that is stated in an introduction." Transitions do not contain the main idea but rather show the relationship between the main idea(s) and the supporting arguments used by the speaker/writer.
Thus, the correct answer is the fourth option.