Final answer:
Adhesion is the attraction between water molecules and different substances, and cohesion is the attraction between water molecules. These properties are critical for processes like plant water transport and insect movement on water surfaces.
Step-by-step explanation:
Adhesion and cohesion are fundamental properties of water that allow it to interact with itself and other substances. Adhesion is the tendency of water molecules to cling to other types of surfaces due to intermolecular forces, which can be observed when water spreads out on a surface.
Cohesion, on the other hand, is the attraction between water molecules themselves, creating a tendency for water to form droplets. These forces are crucial for various biological processes, such as the transport of water from the roots to the leaves in plants through capillary action, which relies on the balance between cohesive and adhesive forces.
Water's capillary action is an example of how adhesive forces can sometimes be stronger than cohesive forces when the water interacts with charged surfaces, like the inside of capillary tubes. This phenomenon enables plants to pull water and essential nutrients upwards against gravity, sustaining life. Insects like the water strider can walk on water due to the high surface tension created by the cohesive forces between water molecules, which is also facilitated by the adhesive forces between their feet and the water surface.