Which of the following statements about human impact on ecosystems is correct?

• A. Ecosystems are unaffected by human activities other than pollution.
• B. Humans can alter ecosystems through activities such as deforestation, urbanization, and pollution.
• C. Pollution is the only way that humans can cause changes to ecosystems.
• D. Only natural events, not human actions, can change ecosystems.

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by understanding the concept of ecosystems. Ecosystems are communities of living organisms interacting with their physical environment, and they are influenced by both natural events and human activities.
2. Step 2: Analyze the first statement: 'Ecosystems are unaffected by human activities other than pollution.' This is incorrect because human activities such as deforestation, urbanization, and agriculture also significantly impact ecosystems beyond just pollution.
3. Step 3: Evaluate the second statement: 'Humans can alter ecosystems through activities such as deforestation, urbanization, and pollution.' This is correct because these activities can lead to habitat destruction, loss of biodiversity, and changes in ecosystem dynamics.
4. Step 4: Examine the third statement: 'Pollution is the only way that humans can cause changes to ecosystems.' This is incorrect because, as mentioned earlier, human activities like deforestation and urbanization also cause significant changes.
5. Step 5: Review the fourth statement: 'Only natural events, not human actions, can change ecosystems.' This is incorrect because human actions are a major driver of ecosystem changes, often more impactful than natural events in modern times.