Biochemistries

Most life in Known Space shares similar biochemistries, since they evolved from the Thrintun practice of seeding barren worlds with food yeast which they used to feed their slaves.

Other exotic element-based biochemistries * Boranes are dangerously explosive in Earth's atmosphere, but would be more stable in a reducing environment.

The possibility of life-forms being based on "alternative" biochemistries is the topic of an ongoing scientific discussion, informed by what is known about extraterrestrial environments and about the chemical behaviour of various elements and compounds.