Which category of bacteria is most abundant in nature and is helpful in making curd from milk and in the production of antibiotics?

According to Bradley and Carr,the nitrogen fixation takes place in

Assertion: Gram-negative bacteria do not retain the stain when washed with alcohol.
Reason: The outer face of the outer membrane of Gram-negative bacteria contains lipopolysaccharides,a part of which is integrated into the membrane lipids.

Which of the following is $NOT$ a shape of bacteria?

What are organisms that obtain energy from reduced inorganic compounds called?

Assertion $A$: Some bacteria possess unique phenotypic characters.
Reason $R$: Many bacterial cells contain plasmid $DNA$ in addition to genomic $DNA$.
Which option is correct for Assertion $A$ and Reason $R$?