How many categories are bacteria divided into based on their shape?

Which kingdom includes prokaryotic organisms?

Choose the correct statements $(i - iv)$ regarding mycoplasma:
$(i)$ Mycoplasma has no cell wall.
$(ii)$ Mycoplasma is the smallest living organism known.
$(iii)$ Mycoplasma cannot survive without $O_2$.
$(iv)$ Mycoplasma are pathogenic in animals and plants.

Biochemical resemblance is generally used for the identification of which group of individuals?

Spliceosomes are not found in the cells of .............

$P$ - Assertion: Some bacteria are Gram-negative.
$Q$ - Reason: Gram-negative bacteria do not retain the Gram stain.