In the real world you can't really boil someone down to being just one race (and the concept itself is actually a bit off by itself), but in the world of Placeholder people are in fact boiled down to a single race. The base races are all shown below
Humans have the same general appearance as humans from Earth. Yeah. Shocker there.
Elves tend to be lither and taller and also sport pointed ears. They rarely grow facial hair.
Dwarves are generally shorter and thicker and generally have thick beards (at least, on the males).
Beastborn are similar to humans except that they have an animal trait included (e.g. animal ears, a tail)