Pollution Quiz
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5 questions, one answer each
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1. What is the primary effect of excess fertiliser entering an aquatic ecosystem?
- A. It increases the growth of algae and other aquatic plants due to enrichment with nitrates and other mineral ions
- B. It directly poisons fish and other aquatic organisms
- C. It reduces the temperature of the water
- D. It increases the pH of the water, making it more alkaline
2. Which statement correctly describes the process of eutrophication?
- A. Algal growth reduces, leading to increased oxygen production and fish survival
- B. Increased decomposition of algae by decomposers uses up dissolved oxygen, causing organisms requiring oxygen to die
- C. Fertiliser directly blocks light from reaching aquatic plants
- D. Sewage introduces predators that eat all the fish in the ecosystem
3. Why are non-biodegradable plastics particularly problematic in ecosystems?
- A. They decompose quickly and produce toxic chemicals
- B. They cannot be broken down by decomposers, so they persist in the environment for many years and can harm organisms through ingestion or entanglement
- C. They only affect terrestrial ecosystems, not aquatic ones
- D. They improve soil quality by increasing mineral content
4. What is the relationship between methane and carbon dioxide emissions and climate change?
- A. These gases reflect all incoming solar radiation back to space
- B. These gases are non-biodegradable and accumulate as litter
- C. These gases trap heat in the atmosphere, enhancing the greenhouse effect and causing global temperatures to rise
- D. These gases only affect air quality and do not influence temperature
5. Untreated sewage is discharged into a river ecosystem. Explain why the dissolved oxygen concentration in the river decreases as a result of this pollution.
- A. The sewage introduces oxygen-consuming bacteria that decompose organic matter in the sewage, and aerobic respiration by these decomposers uses up dissolved oxygen from the water
- B. Sewage particles physically block oxygen from dissolving into the water
- C. The nitrogen in sewage immediately kills all aquatic plants that produce oxygen
- D. Sewage reduces water temperature, causing oxygen to be released into the air instead