What is dispersal of seeds? State four agents of dispersal.

Properties of oxygen: Oxygen is a colourless, odourless, and tasteless gas. It supports combustion of substances. It is essential for respiration in living organisms. It is slightly soluble in water. It is denser than air (relative density 1.11). Step 1: List three components of a solar panel. 1. Photovoltaic (solar) cells made of silicon. 2. Tempered glass cover. 3. Aluminium frame. Step 2: State names of two products formed (magnesium with steam/water). Magnesium + steam magnesium hydroxide + hydrogen Mg + H2O -> Mg(OH)2 + H2 Products: Magnesium hydroxide and Hydrogen gas. Step 3: Distinguish between mass and weight and state their units. Mass is the amount of matter in an object. It is a scalar quantity and remains constant. Unit of mass: kg. Weight is the gravitational force on an object. It is a vector quantity and changes with location. Unit of weight: N (newton). Step 4: Explain three differences between liquid fuels and gaseous fuels. 1. State: Liquid fuels are in liquid form (e.g., petrol, diesel). Gaseous fuels are in gaseous form (e.g., LPG, natural gas). 2. Storage: Liquid fuels are stored in tanks at atmospheric pressure. Gaseous fuels require high-pressure cylinders. 3. Transportation: Liquid fuels are easier and safer to transport. Gaseous fuels need special pipelines or cylinders. Step 5: Distinguish between evaporation and boiling. Evaporation occurs only from the surface of liquid, at any temperature below boiling point, slow process. Boiling occurs throughout the liquid, at fixed boiling point, rapid process with bubbles. Factors affecting rate of evaporation: 1. Temperature: Higher temperature increases rate. 2. Surface area: Larger area increases rate. 3. Wind speed: Faster wind increases rate. 4. Humidity: Lower humidity increases rate. Step 6: Explain conduction of electricity in electrolytic solutions (which conducts most). Electrolytic solutions conduct electricity due to ions (charged particles) moving towards electrodes. Strong electrolytes (e.g., NaCl) dissociate completely, conduct most. Weak electrolytes (e.g., acetic acid) dissociate partially, conduct less. Strong solutions conduct the most electricity.