The magma carta has what effect on English monarchs?

The correct answer is:

Monarchs had to respect certain basic rights of citizens.

The Magna Carta, Magna Carta Libertatum (latin) which means "The Great Charter" is a charter issued by King John of England, which established for the first time that everybody, including the king should obey the law. It basically was the start of protecting the rights of the citizens, and limited the monarchs power. This charter was created to deal with the political crisis in 1215.