You have just created a replication slave from a backup of the master made with mysqldump:

You try to log in to the slave with the application user, but fail as follows:

The login works on the master.
Which two changes to the process can fix the issue?

A simple master-to-slave replication is currently being used. This information is extracted from the SHOW SLAVE STATUS output:

You execute a `SHOW CREATE TABLE mytable" on the slave:

The table mytable on the slave contains:

You have issued a STOP SLAVE command. You have determined that it is safe to skip the transaction in this case. One or more statements are required before you can issue a START SLAVE command to resolve the duplicate key error. Which statement should be used?

After analysis on the slow query log on a high-end OLTP service, the table identified in the slow queries is:

What are the two most likely reasons for the slowness given this output? (Choose two.)

SQL injection is a common security threat.
Which two methods would help protect against this risk? (Choose two.)

After rebooting the host, you attempt to start the mysqld service. You get the following error:
Can't start the server: Bind on TCP/IP port: Address already in use
What is the most likely cause of this error?