Answer:
Marking mortal privation when firmly in place. An enduring summation inscribed in my face.
People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?
What dress does everyone have, but no one wears?
I have roots nobody sees. I am taller than trees. Up up I go but I never grow.
I march before armies, a thousand salute me. My fall can bring victory, but no one would shoot me. What am I?
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.