In members of which kingdom,nuclear membrane is absent?

Antony van Leeuwenhoek was the first to discover bacteria. He belonged to which country?

In some cyanobacteria,pigment-containing membranous extensions are called ..........

Spirochaetes are ...

What is the full form of $E. coli$?

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.