Who answers correctly will get brainliest ( ◠‿◠ )

Note: I will reveal the answer if two people has answered , if both of them got it correctly or both got the same answer , none of them will get the brainliest tittle on my question. You can only guess once

Riddle: I have two characteristics But in one body I only have one

( sorry if the riddle doesn’t make sense because it will make it obvious )