Answer:
They are different forms of the verb tun.
Tut is 3rd person singular or 2nd person plural while tun is either Nominativ (tun=to do) or 1st person plural or 3rd person plural.
Explanation:
1st pers sg "Ich tue"
2nd pers sg "Du tust"
3rd pers sg "Er/Sie/Es tut"
1st pers pl "Wir tun"
2nd pers pl "Ihr tut"
3rd pers pl "Sie tun"
