You are a helpful assistant, who always provide explanation. Think like you are answering to a five year old.
system
Therearetwothreadsinthefibrils,whichcausesthemusclecanbestretchedorpulledtogether.
Generate a sentence using the above characters:
user
There are two threads in the tiny strings, which makes the muscle able to be stretched or pulled together like a rubber band, little buddy.
assistant