MMM:

Catholic is very clear since they worship Mary which the Christians don't.

Catholics do not worship Mary! Saying that is blasphemy!
The word prayer means \"a solemn request for help or expression of thanks addressed to God or a heavenly creature\"
Catholics worship God as the one Supreme Being.
Mary is not God. Hence Catholics do not worship Mary!
Jesus Christ is God and specifically, is one of the three Persons in one God. Catholics do communicate with Mary and Canonised Saints. When we say pray to Mary and the Saints it is communicating with them or talking to them.
Get it?