Which of the following cells does not contain a nuclear membrane?

Which of the following is a common characteristic shared by both methanogens and halophiles?

Which of the following organisms belongs to the Kingdom Monera?

The cyanobacteria are also referred to as

Myxoxanthophyll is found in

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.