Read the following article and answer the question. Article: As summer arrives, it's important to drink more, to keep us cool. Let's look to see what drinks are popular in the US. Sports drinks and fruit drinks are quite popular. But there are two main drinks that Americans enjoy most: water and soda. Around 10.9 billion gallons of water is drunk each year, and 12.8 billion gallons of soda. Soda is the most popular drink. It's fizzy and enjoyed with friends. Perhaps it is the drink of choice for parties. However, if you are playing sports, soda is not a good drink. The fizzy and sweet drinks may make you uncomfortable while exercising. The best drink for sports is water. That's because it has no calories and keeps you fresh during sports. Besides, doctors tell us that drinking water each day is healthy. For many kids, juice or milk are their favorites. These drinks are healthy and give kids vitamins and energy during the day. Adults usually choose between tea or coffee. Question: People like to drink water for sports because _ . Answer:
it has no calories