National 5 Biology - Life on Earth Questions and Answers | Latest Version | 2025/2026 | Correct & Verified

National 5 Biology - Life on Earth Questions and Answers | Latest Version | 2025/2026 | Correct & Verified What is meant by a "biotic factor" in an ecosystem? A biotic factor is a living component of an ecosystem, such as plants, animals, or microorganisms. What is meant by an "abiotic factor" in an ecosystem? An abiotic factor is a non-living component of an ecosystem, such as temperature, sunlight, water, and soil. What role do producers play in an ecosystem? Producers, usually plants and algae, make their own food through photosynthesis and form the base of the food chain. What is the primary source of energy for most ecosystems on Earth? The primary source of energy is the Sun, which provides energy for photosynthesis in producers. 2 What is a food chain? A food chain is a linear sequence of organisms through which energy and nutrients are transferred, starting with producers and moving to consumers. What is a food web? A food web is a more complex and interconnected system of food chains in an ecosystem, showing the multiple feeding relationships between organisms. What is a trophic level? A trophic level is each step in a food chain or food web, representing the flow of energy through an ecosystem. What is meant by "energy loss" between trophic levels? Energy is lost between trophic levels due to metabolic processes such as movement, reproduction, and heat production, making only a small portion of energy available to the next level. What is the role of decomposers in an ecosystem? 3 Decomposers, like bacteria and fungi, break down dead organisms and organic waste, recycling nutrients back into the ecosystem. What is the significance of nitrogen fixation in an ecosystem? Nitrogen fixation is the process by which nitrogen gas from the atmosphere is converted into compounds usable by plants, primarily carried out by certain bacteria. What is the carbon cycle? The carbon cycle describes the process by which carbon is exchanged between living organisms, the atmosphere, and the Earth's