Which of the following best describes flagellates within the domain Eukarya?

• A. They are eukaryotic organisms that move using one or more whip-like flagella.
• B. They are prokaryotic organisms that lack a nucleus.
• C. They are multicellular fungi that form hyphae.
• D. They are eukaryotic organisms that reproduce only by binary fission.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the domain Eukarya, which includes organisms with cells that have a true nucleus and membrane-bound organelles.
2. Step 2: Recognize that flagellates are organisms characterized by their use of flagella, which are whip-like structures used for movement.
3. Step 3: Recall that flagella in eukaryotes are structurally different from those in prokaryotes and are used for locomotion in many single-celled eukaryotic organisms.
4. Step 4: Eliminate options that describe prokaryotic organisms (which lack a nucleus) or multicellular fungi (which form hyphae), as these do not fit the description of flagellates within Eukarya.
5. Step 5: Confirm that the best description is that flagellates are eukaryotic organisms that move using one or more whip-like flagella.