Question

1. which structure is found in all cells and controls what enters and leaves the cell?

a. cytoplasm
b. nucleus
c. cell membrane
d. cell wall

Explanation:

To solve this, we analyze each option:

• Option a: Cytoplasm is the jelly - like substance within the cell, not for controlling entry/exit.
• Option b: The nucleus contains genetic material and is not for controlling what enters/leaves the cell.
• Option c: The cell membrane (also called plasma membrane) is present in all cells (prokaryotic and eukaryotic) and acts as a selectively permeable barrier, controlling the movement of substances in and out of the cell.
• Option d: Cell walls are present in plants, fungi, and some bacteria, but not in animal cells, so they are not found in all cells.

Answer:

c. Cell membrane