Answer:
What does a WW1 Trench, A Submarine and a Popular Phone App all have in common?
Runs smoother than any rhyme, loves to fall but cannot climb!
A thousand colored folds stretch toward the sky. Atop a tender strand, rising from the land, until killed by maiden's hand. Perhaps a token of love, perhaps to say goodbye.
You can hold it without using your hands or your arms. What is it?
It doesn't live within a house, nor does it live without. Most will use it when they come in, and again when they go out.
A leathery snake, with a stinging bite. I'll stay coiled up, unless I must fight.