Which of these fits gap 20?

Directions: Complete this passage by selecting the most suitable option for the corresponding gap.
Long, long ago, when humans _______(17)______ the world, they used to live in groups. These forms of early groups are what we call tribes.
The members of a tribe hunted together, fought together, ate together, and slept together _____(18)_____ caves or primitive dwellings owned by the tribe.
The food brought in by the hunters or farmers _____(19)______ to the entire tribe, and cooking was done in common.
This was the time when there _______(20)______ still no families, as you know families today.