The link between prokaryotes and multicellular eukaryotes is ......... .

Which of the following groups of kingdom $Protista$ is being described in the statements given below?
$(i)$ This group includes diatoms and golden algae.
$(ii)$ They are microscopic and float passively in water currents (plankton).
$(iii)$ Most of them are photosynthetic.
$(iv)$ They have deposits in their habitat; this accumulation over billions of years is referred to as 'diatomaceous earth'.

$A$ stiff cell wall and biflagellate cells are characteristic features of which group?

Write the characteristic features of the group Dinoflagellates.

The presence of macronucleus and micronucleus is a characteristic feature of $......$.

Nosema belongs to which phylum?