sorry if this is a basic question, but I was reading about the permutation group $S_3$, and I read that it has three subgroups: $\langle y\rangle$, $\langle xy\rangle$, $\langle x^2y\rangle$ of order 2 and $\langle x\rangle$ of order 3.
Can someone mention which subgroups these are, and how to determine their order? are any of these groups normal?