The importance of cystine lies in the fact that it is
an essential precursor to our bodies» most important natural antioxidant: glutathione.
Iodine, the heaviest of the halogens, is required in proper quantities as
an essential precursor to thyroid hormone synthesis.
Specifially, NAC is a derivative of the amino acid L - cysteine,
an essential precursor used by the body to produce glutathione.
This amino acid is
an essential precursor to nitric oxide (NO).
This process, which was
an essential precursor to the marine reserve, was funded by TAT.
I'd argue that one of
the essential precursors to walking simulators is the cult - classic horror game Amnesia, and Lake Ridden clearly takes a lot of inspiration from Amnesia.
While not a metroidvania in and of itself,
this essential precursor defined the workings of exploratory gameplay and persistent imaginary worlds.
Most important too is the fact that it became
an essential precursor to the so called Neo-Expressionist artists of the 1980s.
A preliminary investigation is
an essential precursor to a fair disciplinary process.