Question

why methane a fundamental or parent hydrocarbon

Answer 1

bcoz in methane 4 electrons of carbon make bond with each electron of different hydrogen

Answer 2

This is because methane is the simplest Alkane containing one carbon which bonds with to four hydrogen atoms.
From methane a methyl can be derived. The methyl contains one carbon bonded to three hydrogen atoms. The methyl is a very stable hydrocarbon and occurs in many organic compounds and this makes methane to be a parent hydrocarbon.