Is it informal letter or formal letter
- North America has a long, rich history in ultrarunning, one that stretches back thousands of years. ... On their runs they would carry a dried buffalo heart. .... This ability to cover ground on foot was of paramount importance. ... The came over, when there was still ice connecting Asia to America, they came ...
So if there is no topic sentence than it would really not sum up your arguement in the paragraph or the point you are stating