Question

which statement about the cell membrane is true?
it contains cellulose and sugars that are involved in communication.
it is present in animal cells only.
it is rigid and elastic for supporting the cell’s shape.
it prevents harmful substances from entering a cell.

Explanation:

• Analyze each option:
• Option 1: Cellulose is in plant cell walls, not cell membranes. So this is false.
• Option 2: Cell membranes are present in both animal and plant cells (plant cells also have a cell wall outside the membrane). So this is false.
• Option 3: The cell membrane is flexible, not rigid. The cell wall (in plant cells) is rigid for support. So this is false.
• Option 4: The cell membrane is selectively permeable, meaning it can prevent harmful substances from entering the cell while allowing necessary ones in. This is true.

Answer:

It prevents harmful substances from entering a cell.