Can somebody revise or correct my sentences? and can you add a funny thing?

Drinking Soda
Soda is one of the most popular soft drinks here in the Unite States. Maybe it is the caffeine that makes soda taste so good, or maybe it is the sugar. Soda is now a household item, just like milk. There is a study showed that the United State is the most country that it’s people drinking soda. The average American drinks about 65 gallons of soda a year. The largest customers for soda are teenagers and children. According to the Centre for Science, teenagers in the United States now drinking soda twice as much as milk. Fifty-six percent of 8-year-olds down soft drinks daily. We have all to think about the harmful effects of this drink in our bodies. Soda causes many health problems that everyone can suffer from like fattiness, tooth decay, and caffeine dependence.
Recently a study showed a strong link between drinking soda and childhood obesity, that is because of the big amount of sugar that a can of soda has which is about ten teaspoons of sugar. It is made sure that sugar can be cause to high blood pressure, high cholesterol and heart diseases. Soda includes a high amount of calories too, almost 150 calories per 12 once can. In my opinion the main cause for why children like to drink soda is that soda is available in school.
Second, tooth decay. Newly a study showed nearly 3200 Americans 9 to 29 years old who drink soda have tooth decay. Not just because of the high level of sugar in soda, but because of all element in soft drinks that cause tooth problems. The acids in soda pop are also notorious for etching tooth enamel in ways that can cause to cavities.
Third, I will talk about caffeine dependence. Soda like coffee includes large amounts of caffeine. Even sofa drink industry agrees that caffeine causes the same effects in children as adults, therefore, people who drink soda because addicted on it because their need for the caffeine. Soda contains an average of 35 to 38 milligrams per 12 ounce can. Even diet sodas which are usually chosen by those who are trying to control calories and sugar often pack a lot more caffeine than regular soda.

If you are still drinking soda this is something that is quite simple to stop. In my mind there is absolutely no justification and reason to drink soda. Both sugar and NutraSweet are deadly to your health and will gradually rob you of it. So stick to pure water.