Ciliates differ from all other protozoans in

Question

Accepted Answer

B. 1. Recall the unique nuclear feature found in ciliates, such as *Paramoecium*, that is not seen in other protozoan groups.
$$
	ext{Ciliates} ightarrow 	ext{Macronucleus + Micronucleus}
$$

2. Note that a **macronucleus** controls the metabolic (vegetative) functions of the cell, while a **micronucleus** is involved in genetic exchange during conjugation — this dual-nucleus condition is exclusive to ciliates among protozoans.

3. Rule out the other options: contractile vacuoles are common in many protozoans (not unique to ciliates), flagella are used by flagellates (not ciliates), and pseudopodia are used by amoeboid protozoans.

Hence, the correct answer is **Option B, having two types of nuclei**.