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.

The ropes supplied to the Royal Navy are made from various kinds of vegetable fibre which may differ in strength, weight, flexibility, hardness or resistance to wear, elasticity, resistance to weather, or behaviour when wet.
The ropes

It is grown in Kenya, Tanganyika, Haiti and Java and, when new and untreated, is hairy and of a pale straw colour.
It

All three should be spread about one-third of the boat's length apart.

All three