Question

1. cell membranes are said to be semi - permeable. what does this mean?

Explanation:

Cell membranes being semi - permeable means they allow certain substances (like small molecules, water) to pass through while restricting others (like large molecules, some ions). This property is crucial for maintaining the cell's internal environment, regulating the entry of nutrients and exit of waste, and responding to the external environment.

Answer:

Cell membranes are semi - permeable, which means they allow some substances to pass through while blocking others. This selective permeability is essential for the cell's survival and proper functioning.