Add higher life-forms before anything competitive can evolve.
Not when higher life-forms are the very thing the invaders desire.
Planets where the mutation rate was big enough to create higher life-forms, leaving the fossils Horis showed us earlier.
One great mystery is why sexual reproduction became dominant for higher life-forms.
No life-forms higher than deep sea algae remain on a world that, to judge by the artifacts left behind, had an advanced civilization.
The "high powers" are the highest known life-forms.
There is only one area in which higher life-forms are present in great enough concentration to register despite the interference.
"The artifact appears to know when a higher life-form wishes to penetrate the field."
Appetite exists in all higher life-forms, and serves to regulate adequate energy intake to maintain metabolic needs.
I'm not getting communications from any higher life-forms.
