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National 5 Biology - Unit 3 Questions and Answers | Latest Version | 2025/2026 | Correct & Verified
What is a population?✔✔A group of organisms of the same species living in the same area at the same time.
What is meant by biodiversity?✔✔The variety of different species of living organisms in an ecosystem.
What is the term for the role an organism plays in an ecosystem?✔✔Niche
Why is it important to maintain high biodiversity in an ecosystem?✔✔It increases stability and resilience against changes or disease.
What happens if two species occupy the same niche?✔✔They compete and one may be outcompeted and die out.
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What is a producer?✔✔An organism that makes its own food using photosynthesis.
What is a consumer?✔✔An organism that eats other organisms for energy.
What is a predator?✔✔An animal that hunts and kills other animals for food.
What is a food web?✔✔A network of interconnected food chains showing energy flow in an ecosystem.
What is the source of energy for most ecosystems?✔✔Sunlight
What is a decomposer?✔✔An organism that breaks down dead material to recycle nutrients.
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How is energy lost between each level of a food chain?✔✔Through movement, heat, and undigested materials.
Why are food chains usually short?✔✔Because too much energy is lost at each level.
What is a limiting factor?✔✔A condition that restricts the growth or survival of an organism.
Give an example of a biotic factor.✔✔Competition for food
Give an example of an abiotic factor.✔✔Temperature
What is a quadrat used for?✔✔To estimate population size of plants or slow-moving animals.
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