Multiple choice

The outer boundary of the cell is called ____.

  1. cytoplasm

  2. plasma membrane

  3. protoplasm

  4. nucleus

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The plasma membrane (also called cell membrane) is the outer boundary that separates the cell from its external environment. It controls what enters and exits the cell. Cytoplasm is inside the membrane, protoplasm includes all living contents, and nucleus is the central organelle.