We know, who an advocate is??. An advocate is a person who speaks for you. Now, have a close look at the word "advocate". It is combination of ad-(prefix) and vocare(a root, which means "to call" ).

 

Let's look at some words, which have the same root vocare.

 

invoke (in + voke): to call on.

Usage: The government will invoke the law.

 

provoke (pro=before + voke) : to deliberately act in a way intended to anger someone.

Usage:  Pakistan is trying to provoke India.

 

convoke (con=together + voke): to call together for a meeting. 

Usage: The president convoked the parliament.