Answer:
2 and 5
Step-by-step explanation:
Transitional expressions can bring together ideas, making the whole thing flow better. They can show the structure of a text (2) and they can add interest (4) but those are not their primary functions, and there are other things in writing that do each of those better.
Transitional expressions reveal connections between ideas, such as why they are related, why this is the order chosen, and how the writing then makes sense. They help readers move from idea to idea by showing why it is logical to proceed a certain way. Thus, it is 2 and 5.
Hope this helps you!