Which of the following is the coloured portion in the cell of $Nostoc$?

Which of the following statements is incorrect regarding $Mycoplasma$?

Some bacteria are not easily killed because of:

$......$ bacteria oxidise various inorganic substances such as nitrites,ammonia and use the released energy for $\text{ATP}$ production $:-$

To which kingdom does the organism in the given figure belong?

Which of the following is a free-living,aerobic,non-photosynthetic,nitrogen-fixing bacterium?