It is the Yarn that makes it strong.
Levis jeans are made from Ne 10 to Ne 12 yarn (or 590Tex to 490
Tex), Ne 10 yarn is defined as: Yarn the thickness of which a pound
(lbs) of fibre can be twisted into 7800 yards.
Ne 1 yarn is where the thickness of yarn whereby a pound of fibre
is twisted to 780 yards.
They use a fibre grade that is obtainable from fresh raw materials
(much of the textile tradein Asia now uses recycled yarn)
Fresh raw materials (meaning using cotton fresh from the plant),
generally have long fibres with fibre strands up to 70mm long.
Recycled fibres are usually only 30mm long or shorter.
When long fibres are twisted, their bond is stronger and thus makes
the jeans stronger.
It's just like braided steel wires where it can hold several tons
where a single steel wire usually snap.
