In human cells, ___________________ are used to move a cell within its environment while ___________________ are used to move objects in the environment relative to the cell.

• A. Cilia, pseudopodia.
• B. Flagella; cilia.
• C. Cilia; flagella.
• D. Microfilaments; microtubules.

Answer: (B)

Verified step by step guidance

1. Understand the function of cilia and flagella: Cilia are hair-like structures that can move fluid or objects across the cell surface, while flagella are tail-like structures that propel the cell itself through its environment.
2. Recognize the role of microfilaments and microtubules: Microfilaments are involved in cell movement and shape changes, while microtubules are part of the cell's cytoskeleton and help in moving organelles and other structures within the cell.
3. Identify the correct pairing for cell movement: Flagella are used to move the cell itself, while cilia are used to move objects or fluid relative to the cell.
4. Consider the context of the question: The question is asking for structures that move the cell and structures that move objects relative to the cell.
5. Select the correct answer based on the functions: The correct answer is 'Flagella; cilia' because flagella move the cell and cilia move objects in the environment relative to the cell.