How People Influence Natural Systems

What type of ecosystem is created where freshwater meets saltwater, such as in San Francisco Bay?

• Rainforest

• Desert

• Estuary

• Glacier

What is one negative environmental impact of using road salt in Chicago during winter?

• It makes roads too slippery for cars.

• It causes air pollution in cities.

• It contaminates water and harms plants and animals.

• It increases the temperature of lakes and rivers.

Why have people in the Florida Keys built barriers such as seawalls, dams, and gates?

• To create more land for farming.

• To block rising sea levels and prevent flooding.

• To keep fish from swimming into residential areas.

• To stop hurricanes from forming.

Which of the following is an example of human activity affecting an estuary ecosystem?

• Shipping and farming in San Francisco Bay.

• Planting trees in a desert.

• Building dams to create artificial lakes.

• Mining for coal in mountain regions.

What is the main challenge highlighted in all three locations in the US?

• The need for more freshwater sources.

• The impact of climate change and human activities on natural systems.

• The spread of wildfires in urban areas.

• The construction of new cities on islands.