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 through its environment.
2. Consider the role of microfilaments and microtubules: Microfilaments are involved in cell movement and structure, while microtubules are part of the cell's cytoskeleton and help in moving organelles and other structures within the cell.
3. Identify the correct pair for moving the cell and moving objects relative to the cell: Flagella are typically used for moving the cell itself, while cilia are used to move objects or fluid around the cell.
4. Review the options given: The correct answer should match the functions described above, where flagella are used for cell movement and cilia for moving objects relative to the cell.
5. Select the correct answer based on the understanding of these structures: The correct choice is 'Flagella; cilia' as flagella move the cell and cilia move objects in the environment relative to the cell.