1. Bacteria

1.1 Basic needs, classification

Bacteria need very little water, and a moist atmosphere may be all they need. That's why they can be found in all environments: air, water, earth.

The need or otherwise for oxygen to enable bacterial growth has led to their division into different groups: strict aerobic, facultative anaerobic, strict anaerobic.

Another element essential to their survival is carbon. They can find it in the form of CO ₂ , these bacteria are known as "autotrophs". Heterotrophs use organic carbon sources.

They are also known by other names, depending on the pH of the environment in which they thrive: acidophilic (0 < pH < 6), neutrophilic (6 < pH...