Answer:
Most people that age aren't mentally developed enough to form a solid political opinion.
He’s going to fast, he’s gana die!
You would need to introduce a list.
For example you could have: My shopping list contains of; milk, bread, and yogurt.
Another purpose is to separate clauses.
Answer:
Marines arrive at a human settlement on a distant planet, and find that the colony has been destroyed by hostile aliens
The topic sentence is the starting sentence and what you’re talking about
