Concept:A layout in which houses are not orderly arranged is an unplanned (haphazard) settlement. Houses are often built in waterways and leave no room for roads and drains.
Solution:Because buildings block the natural flow of water and there are no proper drains, heavy rain quickly turns into floods. So such a layout is likely to produce rainfall disasters such as flooding.
The other options describe the opposite of what happens:
B: pipes and water facilities are hard to lay through scattered, crowded houses.
C: haphazard building leads to slums; it does not prevent them.
D: houses packed without order let fire and disease spread easily, and fire tenders and rescue teams cannot reach them.
Key point: The stored key (D) is wrong: a disorderly layout helps disasters to spread; it does not prevent them.
Answer:Option A (produce rainfall disasters.)