Its not an obligatory?

Baptism is an obligatory Sacrament for, without it, no other Sacraments can be received, and Our Blessed Lord, Himself, said the we must be baptised.

no, zakat is not obligatory, if u can afford it then its obligatory on you to pay it

essential, compulsory, required, necessary, enforced, requisite, mandatory, binding

An obligatory parasite is a parasite which totally dependent on others for survival.

Fast or no fast its obligatory to pray 5 times. If you don't pray during Ramadhan then your fasting is like dieting.