Mycoplasma is a:

Membrane-bound organelles are absent in

Which of the following are photosynthetic bacteria?

Heterocysts are found in certain

State two economically important uses of:
$(a)$ Heterotrophic bacteria
$(b)$ Archaebacteria

Which of the following statements are incorrect for $Nostoc$ and $Anabaena$?
$(a)$. Possess tissue level organization
$(b)$. Have heterocysts
$(c)$. Can fix atmospheric hydrogen
$(d)$. They are eubacteria