Precursor

ARPNET is the precursor of the modern Internet.

ARPNET is the precursor of the modern Internet.

ARPNET is the precursor of the modern Internet.

ARPNET is the precursor of the modern Internet.

The precursor to the steel drum is 'tamboo bamboo'.

A precursor is a substance from which a more active substance is derived. For opium, the opium poppy flower could be regarded as a precursor. For marijuana, seeds for growing could be regarded as a precursor ... and so on and do forth.

The precursor cell to blood platelets are megakaryocyte precursor (MkP) cells in the bone marrow.