You can see all the emails you've sent for a sequence in the sequence Emails screen.
You can filter the list of emails to emails with a particular response, like emails that were opened or replied to, by clicking the response at the top of the screen. You can also filter to a particular step's emails by clicking that step on the right.
Each email shows the date it was delivered, and whether it was opened, clicked or replied to. You can:
Read the email body by clicking the email.
Mark the email as bounced from the options icon on the right of the email.
Mark the email as replied from the options icon on the right of the email.