Human Impact on the Environment — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
All plastics is recyclable in every city program.
Corrected: Not all plastics are recyclable in every city program.
Plastic recycling depends on local rules and the resin code printed on each item.
2. Fix the sentence:
Compost piles needs only food scraps to break down quickly.
Corrected: Compost piles need air, moisture, and a mix of greens and browns.
Decomposers require oxygen, water, and balanced carbon-nitrogen materials to work efficiently.
3. Fix the sentence:
Glass bottles loses their quality after one recycling cycle.
Corrected: Glass bottles keep their quality through many recycling cycles.
Glass can be melted and reformed repeatedly without losing strength or clarity.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. Newspapers and cardboard belong in the paper recycling bin.
Paper products are collected together so fibers can be pulped and reused.
2. Banana peels and coffee grounds can go into a compost pile.
Compost piles let microbes break organic matter into nutrient-rich humus.
3. Aluminum cans belong in the metal category at the recycling center.
Metals are sorted, melted, and remade into new cans, saving energy.
4. Empty jars and bottles made of silica belong in the glass bin.
Glass items are crushed into cullet and melted to form fresh containers.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Name two items you should put in a paper recycling bin.
Sample answer: Newspapers and cardboard boxes both belong in the paper recycling bin because they are made from wood fibers.
Paper recycling saves trees and reduces landfill waste each year.
2. Why is composting better than throwing food scraps in the trash?
Sample answer: Composting turns scraps into nutrient-rich soil instead of releasing methane gas in landfills.
Compost cuts methane emissions and creates fertilizer for healthier gardens.