How might a single-celled euglenoid or dinoflagellate use its flagellum?

• A. To move through its aquatic environment
• B. To anchor itself to a substrate
• C. To absorb nutrients from the water
• D. To capture prey by ensnaring them

Answer: (A)

Verified step by step guidance

1. Understand the structure and function of a flagellum: A flagellum is a whip-like appendage that protrudes from the cell body of certain single-celled organisms, including euglenoids and dinoflagellates. It is primarily used for locomotion.
2. Consider the environment of euglenoids and dinoflagellates: These organisms typically inhabit aquatic environments, where movement is essential for survival, whether to find food, escape predators, or reach optimal light conditions for photosynthesis.
3. Evaluate the primary function of the flagellum in these organisms: The flagellum's main role is to enable movement through the water. This is achieved by the flagellum's undulating motion, which propels the organism forward.
4. Analyze the other options provided: Anchoring to a substrate, absorbing nutrients, and capturing prey are not primary functions of the flagellum. Anchoring would require structures like holdfasts, nutrient absorption occurs through the cell membrane, and capturing prey typically involves specialized structures or mechanisms.
5. Conclude that the most appropriate use of the flagellum for a euglenoid or dinoflagellate is to move through its aquatic environment, as this aligns with the known function of the flagellum in these organisms.