(a) : Thermoacidophiles (temperature and acid loving ) archaebacteria are found in hot sulphur springs. Although they are microscopic, single celled organisms, they flourish under conditions which would kill higher organisms. These are aerobic bacteria and have the capacity to oxidize sulphur to H2SO4 at high temperature and high acidity (pH=2.0). Some of them are also able to reduce sulphur to H2S under anaerobic conditions. As a rule, they grow best between 80∘ and 100∘C and several species do not grow below 80∘C.