If a box supporting life was sent out into space on a course with no end, what would its contents be?

All life requires energy and the easiest source would be the sun. So you would put in photosynthetic microbes that live in water to take up the minimum space and have the most diversity for an ecosystem. Now no box can stand the test of time so the box would have to land someplace where life could propagate.

Another choice would be bio-engineer a spaceship that could live in raw space having its own ecosystem in its gut. Splitting in two to reproduce and consuming asteroids to fuel its reproduction needs and living off sunshine to supply its energy needs. It would be kind of a living box you might say.

An oxygen-and-water regeneration machine, a life-cycle machine, a self-powered power generator, and lots of happy pills.

You can't put life in a box.

a colony of lab rats with small radio emission tools around their necks.

a man, a woman & some kind of evergreen

it would be a virgins soul