Answer:
I save lives on the ground and in the air. What am I?
I begin and have no end. Eventually I will be the end of all that has begun.
In buckles or lace, I help set the pace. The farther you go, the thinner I grow. What am I?
I am long and slim works in light. Has but one eye and an awful bite.
What jumps when it walks, but sits when it stands?
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.