The correct answer is option D. "preservation of wetlands".
Explanation:
Wetland are areas of lands that are saturated with water, usually comprised by marshes or swamps. Preservation of wetlands help to reduce the risk of floods because wetlands temporarily store and slow the release of stormwater. It has been reported that areas where wetland have been lost, the chances of flood increases by as much as 80 percent. The government of a flood-prone region would likely reduce the risk of floods by preserving its wetlands.
If you have one sickle cell gene, you have sickle cell trait and you will not develop the sickle cell disease. If you inherit two sickle cell genes, you have sickle cell anemia.