Question

Certain bacteria are able to thrive under extreme environmental conditions such as absence of oxygen, high salt concentration, high temperature or highly acidic environment. What are these bacteria called?

• A. Probacteria
• B. Neobacteria
• C. Hardy bacteria
• D. Archaebacteria

Answer 1

The correct option is D Archaebacteria

Archaebacteria are the oldest organisms living on the Earth. They are unicellular prokaryotes and belong to the kingdom, Archaea. They were first discovered in 1977 and classified as bacteria. Most archaebacteria appear like bacteria, when observed under the microscope. However, they are quite different from bacteria and eukaryotic organisms. Archaebacteria are found in very harsh conditions such as in the volcanic vents or at the bottom of the sea. They can easily survive in such extreme environment as sea vents releasing sulfide-rich gases, hot springs, or boiling mud around volcanoes.

So the correct option is 'archaebacteria'.