ANSWER:
The part which is looked under the microscope is the plasma membrane.
Step-by-step explanation:
The plasma membrane is known as the cell membrane and protects the inter-cellular components from the external environment. The plasma membrane controls and regulates the material which enter and exit a cell.
The plasma membrane comprises of proteins, carbohydrates, and lipids and 'surrounds the cytoplasm of the cell'. The plasma membrane function is to maintain cell potential and helps the 'cytoskeleton' to provide a shape to the cell.