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

In which form is the kingdom $Protista$ not observed?

Two species of Amoeba $X$ and $Y$ were kept in fresh water and adapted to it. Species $X$ developed a contractile vacuole. When both were transferred to sea water and adapted, both $X$ and $Y$ lost their contractile vacuole. From these observations, we conclude that:

Microscopic unicellular animals that lack tissues and organs are:

In which kingdom did Whittaker place the dinoflagellates?

Protists are:
$1.$ Unicellular and prokaryote
$2.$ Unicellular and eukaryote
$3.$ Multicellular and eukaryote
$4.$ Autotroph and heterotroph