All three are necessary for reproduction and the social system.

The system was largely used for black and white reproduction.

Not one of these young people has any respect for historical reproduction.

Which is late enough for reproduction to happen and the gene to be passed on.

"Yes, but you see, on my world it is done only for reproduction."

The pairs stay together only for reproduction, until then, they separate.

There are not two different sorts of us, male and female, coming together for reproduction.

The last two segments are reduced and used for reproduction.

This allows continuous culture without the need for sexual reproduction.