In this task, you are given a sentence. You must find the primary subject in the supplied sentence. The output must be a sub-sequence in the sentence.

Q: As the rope is laid up its length contracts like a coiled spring, giving it a certain elasticity.

A: its length
****
Q: When wet, rope will usually shrink in length in proportion to the amount by which it swells in diameter, but it will recover its original length when dry and after use.

A: rope
****
Q: It is used in the Royal Navy only for small lines and small stuff.

A:
It
****