What are the cricle marks sayin on a weed leef to anyone who grows?

k dont worry im not growin but my buddie is an i gotta say i like watchin them grow but he has lil circle marks on one of his plants they look like someone pushed some kinda small cirlce ting on them they didnt change colours or anythin its still green don no tha best way to explain and oh r the first leafs importanrt i no they usaully die and turn yellow i guess r u supose to ccut them off will it damage it? i do smoke tha stuff but dont grow to worried bout tha pigs but love watcin them grow