Animals, including humans, are necessary to a CELSS to maintain balance with plants.
- HUMANS (AND OTHER ANIMALS): feces, urine, gas, mucus, saliva, sweat, tears, milk, semen, blood, nail clippings, hair, dead skin, heat, and eventually meat and bones.
- PLANTS: unused biomass, garbage, plant oils, O2, CO2, ethylene and other trace gasses, water vapor
- MATERIALS & PROCESSES: oils, soaps, worn out clothing (composed of natural fibers/dyes only), laundry & wash (gray) water, out-gassings (solvents/trace gasses from materials used in the CELSS shell construction and other items inside the CELSS).