Some of My Best Friends Are Human

In an underground orphan center on an overpopulated planet, Tajen Jesmuhr dreams of freedom in a distant wilderness under an open sky. So when offered an interplanetary ecology class with offworld field trips, Taje leaps at the chance. But Taje isn't the only misfit here, where everyone has a tragic past and hidden wounds, and she soon clashes with her teacher and her classmates, including:
A boy with a frightening secret who lost his family to a terrorist plague. A crafty female human-alien chimera whose parents disappeared in a paraspace accident. And a boy with a hidden past and a dead father he still hates.
All may have promising careers ahead of them, but only if they can learn to trust themselves and one another enough to survive an uncaring system and a deadly final exam.
Andre Norton believed in this story, and anyone--young and old--who loves science fiction with interesting characters, alien animals, and interplanetary adventures without war will enjoy it too.