Conjugation in protozoa is found in

The term $...........$ means 'first animals'.

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

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:

Which organism is structurally and functionally unicellular?

In Euglenoids, the stored food is $Paramylum$, which is a .........