Human Impact on the Environment — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. The Great Pacific Garbage Patch is mostly made of ___.
A) Tiny plastic pieces and floating debris
B) Solid metal cans piled high above the waves
C) Crude oil that never broke down
D) Chunks of broken icebergs from the Arctic
Sunlight breaks plastic into microplastics that swirl in the ocean gyre.
2. Melting glaciers raise sea levels MAINLY by ___.
A) Cooling the air above coastal beaches each summer
B) Adding more freshwater into ocean basins
C) Pushing salty water deeper into the seafloor
D) Reflecting more sunlight back into outer space
Melted glacier ice flows into oceans, raising overall global sea levels.
3. Compare ocean cleanup nets vs reducing plastic use. Which judgment is MOST accurate?
A) Cleanup nets alone solve the entire plastic problem forever
B) Reducing use stops new plastic but ignores existing waste
C) Both reducing use AND cleanup are needed for real progress
D) Plastic pollution will fix itself if humans simply wait longer
Cleanup tackles past waste while reduction prevents new plastic from entering.
4. A coastal town bans single-use plastic bags. The BEST predicted long-term outcome is ___.
A) Ocean plastic vanishes from the entire planet within one week
B) All sea animals everywhere instantly become healthy and safe
C) Local plastic litter on beaches drops over many months
D) Plastic factories close worldwide because of this single town
One town's ban reduces nearby plastic pollution slowly but does not solve global issues.
Part B: Fill in the Blank
Write the correct answer on each line.
1. Plastic pieces smaller than a pencil eraser are called microplastics.
Microplastics enter food webs when fish and plankton accidentally swallow them.
2. Large rotating ocean currents that trap garbage are called gyres.
Gyres concentrate floating debris into wide patches of polluted water.
3. A massive sheet of slowly moving land ice is called a glacier.
Glaciers store fresh water; melting adds it to oceans and raises sea levels.
4. Insects like bees that move pollen are called pollinators.
Pollinator decline threatens crops, wild plants, and food supplies worldwide.
5. Global average warming caused by greenhouse gases is called climate change.
Climate change drives glacier melt, stronger storms, and shifting habitats globally.