Which of the following kingdoms consists of organisms that lack membrane-bound organelles?

Which of the following are extreme halophiles and thermophiles?

What is the full form of $PPLO$?

What are Gram-negative bacteria?

The smallest living cells with a cell wall are:

The given characters are seen in which of the following group?
$(i)$ Unicellular,colonial,filamentous,symbiotic or free living.
$(ii)$ The colonies are surrounded by a gelatinous sheath.
$(iii)$ Some can fix atmospheric nitrogen in specialized cells called heterocysts.
$(iv)$ They often form blooms in water bodies.