In which group of organisms do the cell walls form two thin overlapping shells that fit together?

Which of the following organisms is included in the kingdom $Protista$?

Microscopic unicellular animals that lack tissues and organs are:

Which of the following types of unicellular algae reproduce by auxospores,possess a siliceous cell wall,and store food in the form of fats,leucosin,and chrysolaminarin?

The protozoan found in the colon of humans is

The thalloid body of a slime mould $(Myxomycetes)$ is known as