Arrange the causal chain related to urban challenges. 1. Pollution 2. Population 3. Death 4. Disease Choose the most logical progression.

Introduction / Context:
This logical chain links demographic pressure to health outcomes via environmental quality.

Given Data / Assumptions:
Higher population tends to increase pollution; pollution elevates disease risk; severe disease can lead to death.

Concept / Approach:
Order by cause → intermediate ←→ effect sequence.

Step-by-Step Solution:
Population (2) rises.Pollution (1) increases as a consequence.Disease (4) incidence rises due to pollution.Death (3) occurs in severe cases.

Verification / Alternative check:
Epidemiological models often include pollution as a risk factor for morbidity and mortality.

Why Other Options Are Wrong:
Starting with death or disease as causes reverses the chain; placing pollution after disease misses the mediator role.

Common Pitfalls:
Assuming linearity in all contexts; here, the simplified model is appropriate for reasoning.

Final Answer:
2, 1, 4, 3