The fetus does not reside in a sterile intrauterine environment and is exposed to commensal bacteria from the maternal gut/blood stream that cross the placenta and enter the amniotic fluid. This ...

Biosphere 2 - a 1.27-hectare enclosed artificial ecosystem, in the desert, near Tucson, Arizona. Provided to China Daily Survival of fittest may apply beyond Earth, but chances are small for real ...