You have been asked to write an essay about the chemical process of fire. Which of these is the most effective topic sentence for a paragraph in this essay?
There are three reasons why fire is important to the development of mankind: warmth, protection, and cooking.
One of the three elements that are required for fire to burn is oxygen.
O Campfires left unattended can have significant consequences, such as forest fires.
O Flames are the part of a fire that can be seen, and depending on the material being bumed, they can be different colors.