biology
Name a type of specialized cell in plants
Guard cell
• Xylem cell
• Phloem cell
• Root hair cell
What are the signs of a chemical reaction?
• Color change
• Gas production (bubbling or fizzing)
• Formation of a precipitate
• Temperature change (either exothermic or endothermic)
2. Thinking (T): Balance the following chemical equation: H₂ + O₂ → H₂O
What are the primary colors of light?
• Red
• Green
• Blue
• Cyan (in the RGB color model)
Name one greenhouse gas contributing to climate change.
• Carbon dioxide (CO₂)
• Methane (CH₄)
• Nitrous oxide (N₂O)
• Water vapor (H₂O)
How does the structure of the human heart contribute to its function?
• The muscular walls allow the heart to pump blood efficiently.
• The valves prevent the backflow of blood, ensuring one-way circulation.
• The four chambers separate oxygenated and deoxygenated blood.
• The thick left ventricle pumps blood with more force to the rest of the body.
Explain how the law of conservation of mass applies to chemical reactions.
• Mass of reactants equals mass of products.
• No atoms are lost or created during a reaction.
• The total energy in a reaction remains constant.
• The amount of matter involved in a reaction remains unchanged.
Explain why a spoon appears bent when placed in a glass of water.
• Light bends as it moves from air into water (refraction).
• The spoon appears bent because of the change in light’s speed.
• The light rays are refracted at different angles, distorting the spoon’s image.
• The water acts as a lens, altering the shape of the spoon’s reflection.
How do human activities contribute to the greenhouse effect?
• Burning fossil fuels releases CO₂ into the atmosphere.
• Deforestation reduces the number of trees that absorb CO₂.
• Agricultural practices release methane from livestock.
• Industrial processes emit a variety of greenhouse gases into the atmosphere.
Describe the function of the phloem in plants.
• Transports sugars from the leaves to other plant parts.
• Moves nutrients from the roots to the stem.
• Carries plant hormones to regulate growth.
• Facilitates the movement of water and dissolved substances in certain plants.
How might a chemical reaction be used to generate energy in a battery?
• A redox reaction releases electrons that flow through a circuit.
• Chemical reactions between metals and electrolytes produce electrical energy.
• The reaction between zinc and copper creates an electric current.
• Chemical reactions in lithium-ion batteries store energy for later use.
Describe the difference between concave and convex lenses.
Concave lenses converge light rays, creating a focused image.
• Convex lenses diverge light rays, spreading them out.
• Concave lenses form virtual images when used for magnification.
• Convex lenses focus light to a single point (real image).
Explain the role of the ozone layer in protecting Earth from harmful radiation.
• It absorbs most of the sun’s harmful ultraviolet (UV) radiation.
• It prevents the majority of UV-B and UV-C rays from reaching Earth.
• The ozone layer protects living organisms from genetic damage caused by UV radiation.
• It acts as a shield to reduce the risk of skin cancer and cataracts in humans.
How does the digestive system in humans break down food for absorption?
• Enzymes in the mouth break down carbohydrates.
• The stomach acid and enzymes digest proteins.
• The small intestine absorbs nutrients through villi.
• The large intestine absorbs water and forms waste.
How would you use a convex lens to focus sunlight onto a piece of paper?
• Position the lens at the correct distance from the paper to focus sunlight.
• Adjust the lens to concentrate the sunlight into a small, intense spot.
• Use the lens to burn the paper at the focal point.
• Hold the lens at an angle to the sunlight to concentrate it more
What are some actions that individuals can take to reduce their carbon footprint?
• Use public transportation or carpool to reduce fuel consumption.
• Switch to renewable energy sources like solar or wind power.
• Reduce, reuse, and recycle to minimize waste.
• Eat more plant-based foods to reduce the carbon footprint of food production.