Question

Ciliates differ from all other protozoans in

• A. using flagella for locomotion
• B. using pseudopodia for capturing prey
• C. having a contractile vacuole for removing excess water
• D. having two types of nuclei

Answer 1

The Correct Option is D

Ciliates are a unique group of protozoans that are distinct from other protozoan groups due to several characteristic features. The correct answer to the question is that ciliates have two types of nuclei. Here's the step-by-step explanation:

1. Ciliate Characteristics: Ciliates belong to the phylum Ciliophora, and they are characterized by the presence of hair-like organelles called cilia. The cilia are used for locomotion and feeding. However, what truly sets ciliates apart is their nuclear dualism.
2. Two Types of Nuclei: Ciliates possess two distinct types of nuclei within their cells:
   • Macronucleus: This controls non-reproductive cell functions such as vegetative growth. It is responsible for the everyday operations of the cell.
   • Micronucleus: This is involved in reproductive processes and genetic exchange during conjugation.
3. Elimination of Other Options:
   • Using flagella for locomotion: This is a characteristic of flagellates, not ciliates.
   • Using pseudopodia for capturing prey: Amoeboid protozoans utilize pseudopodia, not ciliates.
   • Having a contractile vacuole for removing excess water: While many protozoans, including ciliates, have contractile vacuoles, this feature is not exclusive to ciliates.
4. Conclusion: The defining characteristic of ciliates is the presence of two types of nuclei, which is unique among protozoans. This feature is crucial in distinguishing them from other protozoan groups.