MySQL - If slave is offline and comes back online, does it automatically catch data from master?

MySQL - If slave is offline for a few hours and comes back online, does it automatically catch data from master?

Solution 1:

In MySQL replication, a slave "syncs" its data from the master's transaction log, not directly from the database. The slave stores the last position in that transaction log, so as long as you have not touched that position number on the slave, then as soon as it becomes active again, it will resume executing transactions from that position it left off at. All should be well for you.

Here you go, for your reference:
http://dev.mysql.com/doc/refman/5.0/en/replication-implementation.html