What are the religious duties of a muslim called?

The religious duties of Muslims are called 5 pillars of Islam.

They consist of:

Shahadah: sincerely reciting the Muslim profession of faith.

Salat: performing ritual prayers in the proper way five times each day.

Zakat: paying an alms (or charity) tax to benefit the poor and the needy.

Sawm: fasting during the month of Ramadan.

Hajj: pilgrimage to Mecca.

The answer that fits the blank is WATER. Boutros Boutros-Ghali is a known Egyptian politician and Diplomat. He was also the former United Nations secretary general and according to his prediction as based on the current events, it would be WATER which is the source of conflict in the Middle East and neither oil nor politics.