Which among the following is $not$ a prokaryote?

Which among the following are the smallest living cells,known without a definite cell wall,pathogenic to plants as well as animals and can survive without oxygen?

Which of the following two groups of extremophiles grow in highly acidic habitats $(pH = 2)$?

In blue-green algae,photosynthesis occurs in .........

$Trichodesmium\, erythraeum$,which gives the Red Sea its characteristic red color,is a/an ........

Chemosynthetic autotrophic bacteria like $Nitrosomonas$ obtain energy from $........$ for their $\text{ATP}$ production.