toughened epoxy

Been researching epoxies and came across:

Toughened two-phase epoxy, and less tough single-phase epoxy.

A toughen epoxy is a hard epoxy that’s not brittle?
And it is always more desired than single-phase for hull laminates? ie. higher elongation?

So a high elongation epoxy can be either hard or soft, and further the hard one will be tough and not brittle, cause it is high elongation?

tks, idkfa