Question

What is true for Archaebacteria?
A. All are halophiles
B. All are photosynthetic
C. All are fossils
D. Oldest living organisms

Answer 1

The common characteristic of archaebacteria includes the presence of characteristic tRNAs and ribosomal RNAs. In many archaebacteria, the large peptidoglycan cell walls are replaced by a proteinaceous coat. They belong to the Monera kingdom and are distinct from prokaryotes.

Complete step by step answer: The archaebacteria are described as primitive and single-celled prokaryotic organisms. These are the oldest and ancient living organisms on the earth. The first organisms evolved on the earth are archaebacteria. They can survive in extreme conditions such as halophiles, thermophiles, acidophiles, and methanogens.
The cell membrane of the archaebacteria is composed of glycerol-ether lipids.
The release of methane gas in marshy areas and cow sheds gives off a peculiar odor. This gas is released by methanogens, a group of archaebacteria, belonging to Kingdom Monera.
Thus, the correct option is (D). Oldest living organisms

Additional Information: Bacteria responsible for water pollution create the bloom, resulting in a lack of oxygen in the water. The bacteria are photosynthetic autotrophs, which form their food through the use of sunlight. Cyanobacteria are examples of photosynthetic bacteria in water. Most of the species of cyanobacteria are capable of nitrogen fixation. Azospirillum forms the symbiotic relationship, and Azotobacter is free-living nitrogen fixers. Microbes such as bacteria and fungi can be easily grown on bacteria. Their colonies can be visualized on the nutritive media.

Note: The kingdom Monera is characterized as a group that contains unicellular organisms having a prokaryotic cell organization. The organisms do not possess the nuclear membrane, and the most common example of Monera are bacteria. They contain 70S ribosomes, and the DNA is naked.