Which kingdom incorporates phytoplanktons and zooplanktons?

Bioluminescence is exhibited by

The protozoan found in the colon of humans is

Osmoregulation in $Paramecium$ is a function of . . . . . .

These are simple,predominantly aquatic,unicellular,eukaryotic organisms.

Read the following statements and answer the question given below:
$(i)$ They are saprophytic protists.
$(ii)$ Under suitable conditions,they form an aggregation (called plasmodium) which may grow and spread over several feet.
$(iii)$ During unfavourable conditions,the plasmodium differentiates and forms fruiting bodies bearing spores at their tips.
Which of the following class of protists is being described by the above statements?