Which of the following characteristics is common to all protists?

The diatom frustule or shell is made of:

Which of the following parasites causes the disease known as $Sleeping \text{ } Sickness$?

Which protozoan is unlikely to have a contractile vacuole?

Which of the following statements are correct about slime moulds?
$(i)$ Its thalloid body,Plasmodium,has pseudopodia for locomotion and engulfing organic matter.
$(ii)$ During unfavourable conditions,Plasmodium differentiates and produces fruiting bodies,sporangia.
$(iii)$ Spores possess no true cell wall.
$(iv)$ They are dispersed by air currents.
$(v)$ Being extremely resistant,spores survive for many years.
$(vi)$ Plasmodium can grow up to several feet.
Choose the correct answer from the following options:

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