Very important; of high importance.
Necessary.
Necessary for survival but not synthesized by the organism, thus needing to be ingested.
Being in the basic form; showing its essence.
Really existing; existent.
Having the nature of essence; not physical.
Such that each complementary region is irreducible, the boundary of each complementary region is incompressible by disks and monogons in the complementary region, and no leaf is a sphere or a torus bounding a solid torus in the manifold.
Idiopathic.
A necessary ingredient.
A fundamental ingredient.
Very important.
Invigorating or life-giving.
Containing life; living.
Necessary to continued existence.
Necessary to the continuation of life; being the seat of life; being that on which life depends.
Capable of living; in a state to live; viable.
Relating to the recording of life events.
Relating to, or characteristic of life.