Blue-green algae belong to which of the following groups?

The content of mucopeptide (peptidoglycan) in the cell wall is higher in which of the following?

In the bacterium $Bacillus$ $subtilis$,the cells often become attached from end to end forming long filamentous chains,which are embedded in a mass of mucilage forming a scum layer on the substratum. This is called:

Select the correct pair.

Spirochaetes are ...

Assertion $(S)$: Thermoacidophiles can survive in acidic and high-temperature conditions.
Reason $(R)$: Archaea can survive in extreme conditions.