Cilia and flagella are absent in:

Explanation

Cilia and flagella are absent in in viruses other organisms may contain these structures.1. **Viruses**: Viruses are acellular entities, consisting of genetic material (either DNA or RNA) enclosed in a protein coat (capsid). They lack cellular structures, including cilia and flagella. Viruses do not possess the machinery for movement.2. **Bacteria**: While some bacteria have flagella for locomotion, not all bacteria possess cilia or flagella. Many bacteria move using other mechanisms, like twitching or gliding. The presence of cilia or flagella varies among bacterial species.3. **Protists**: Many protists, which are eukaryotic microorganisms, have cilia or flagella. These structures are commonly used for locomotion and feeding in protists. However, there are exceptions, and not all protists have cilia or flagella. Some may use other structures for movement, such as pseudopods.4. **Lower Animals**: Cilia and flagella are often present in lower animals, including protozoans and various simple multicellular organisms. These structures are used for movement and other functions. Lower animals exhibit a wide diversity in their use of cilia and flagella.In summary, the presence of cilia and flagella varies among different organisms. While they are generally absent in viruses, their presence or absence in bacteria, protists, and lower animals can vary depending on the specific organism and its evolutionary adaptations.