Explain osmosis and plasmolysis and identify the main biological principle demonstrated in the experiment.

Here are the answers to the questions based on the provided notes:

a) Two biological terms demonstrated or involved in the experiment are:

• Osmosis: The net movement of water molecules across a partially permeable membrane from a region of higher water potential to a region of lower water potential.
• Plasmolysis: The process in plant cells where the protoplast shrinks away from the cell wall due to water loss when the cell is placed in a hypertonic solution.

b) The main biological principle demonstrated by this experiment is osmosis. The experiment shows how plant tissue (Cocoyarn stalk) responds to different external solutions (hypotonic, hypertonic, and isotonic) through the movement of water, leading to changes in length and curvature.