So too are the Ra'zac designed to prey upon humans.

Despite the unusual hue, the lake exhibits no known adverse effects upon humans.

"When used upon humans, it has the harmless effect I described," he said.

And surely it's incumbent upon us humans not to act like, well, animals, but to think about the endpoint of our actions?

They decide upon humans for this mission, and introduce the promotion on Earth.

Unlike others of his kind, he is fully sentient and looks down upon humans.

These changes have made it entirely dependent upon humans for survival.

The dependence of domestic plants and animals upon humans is part of something much larger than us or them.

An attack known to be by humans and upon humans must touch off the world's last war in which every living thing might die.

This creates revenge from heaven, which befalls upon humans who use up too much natural resources.