Which among the following characteristics is/are shared by Anabaena, Nostoc, and Oscillatoria?

Both (1) and (2)

The correct answer is Option (3) -Both (1) and (2)

(1) Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen, e.g. Anabaena, Nostoc, Oscillatoria, etc. In paddy fields, cyanobacteria serve as an important biofertiliser. Blue green algae also add organic matter to the soil and increase its fertility. Currently, in our country, a number of biofertilisers are available commercially in the market and farmers use these regularly in their fields to replenish soil nutrients and to reduce dependence on chemical fertilisers.

(2) Prokaryotic organisms: Anabaena, Nostoc, and Oscillatoria are all prokaryotes, which means they lack a membrane-bound nucleus and other membrane-bound organelles found in eukaryotic organisms. They are single-celled organisms with a simple cellular structure.

Therefore, the correct answer is (3) Both (1) and (2). These organisms are nitrogen-fixing microbes and belong to the group of prokaryotic organisms.