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SingaporeBiology

Organisms and Their Environment

4 dot points across 4 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How are living things linked by what they eat in an ecosystem?

Describe ecosystems and feeding relationships using food chains and food webs
A focused answer to the O-Level Biology outcome on ecosystems. The key ecological terms, the trophic levels of a food chain, how food webs link chains, and the effect of removing an organism.
8 min answer →

Why are food chains short, and how do decomposers recycle nutrients?

Explain the flow of energy through an ecosystem and the role of decomposers in recycling nutrients
A focused answer to the O-Level Biology outcome on energy flow. Why energy is lost between trophic levels, why food chains are short, and how decomposers recycle nutrients back to producers.
8 min answer →

How do human activities harm the environment, and what can be done about it?

Describe the effects of pollution and deforestation and ways to conserve the environment
A focused answer to the O-Level Biology outcome on human impact. The effects of water and air pollution, the enhanced greenhouse effect, the consequences of deforestation, and ways to conserve the environment.
8 min answer →

How does carbon move between the air, living things and the ground?

Describe the carbon cycle and the processes that add and remove carbon dioxide from the air
A focused answer to the O-Level Biology outcome on the carbon cycle. How photosynthesis, respiration, decomposition and combustion move carbon between the air, living things and fossil fuels.
8 min answer →