🌍 Planet Earth Basics
What is the thin layer of gases surrounding Earth called?
Atmosphere
What kind of waste can turn into compost?
Organic or Biodegradable waste
What gas is the main contributor to the greenhouse effect?
Carbon dioxide (CO₂)
What term describes a species at risk of extinction?
Endangered species
What percentage of Earth’s water is freshwater?
About 3%
Which biome is known for its very low temperatures and permafrost?
A Tundra
What type of waste takes the longest to decompose—plastic, paper, or organic waste?
Plastic
What renewable energy source uses moving air to generate electricity?
Wind energy
What human activity causes deforestation?
Cutting down trees for logging, farming, or construction
What is the main cause of air pollution from cars?
Exhaust gases (carbon monoxide, nitrogen oxides)
What term describes all living and non-living components interacting in a specific environment?
An Ecosystem
Turning old newspapers into new paper products is an example of what?
Recycling
What term refers to the total amount of greenhouse gases produced directly and indirectly by human activities?
Carbon Footprint
Cutting down trees for logging, farming, or construction
Biodiversity
What gas released from burning fossil fuels causes acid rain?
sulfur dioxide (SO₂)
Which biogeochemical cycle involves nitrogen-fixing bacteria converting atmospheric nitrogen into usable forms for plants?
The Nitrogen cycle
How does “closed-loop recycling” differ from “open-loop recycling”?
Closed-loop recycling turns materials into the same product again (like bottles into bottles), while open-loop creates new products (like bottles into clothing fiber).
Explain how ocean acidification is linked to the increase of atmospheric CO₂ and its impact on marine life.
CO₂ dissolves into oceans forming carbonic acid, lowering pH and harming organisms that rely on calcium carbonate, such as corals and shellfish
How does poaching threaten biodiversity beyond just the species being hunted?
Poaching disrupts food chains and ecosystems — removing one species can cause population imbalances, habitat loss for others, and even collapse of entire ecosystems.
What is eutrophication?
When too many nutrients in water cause excessive plant/algae growth and oxygen loss
In which layer of the atmosphere does most weather occur, and why is it significant for sustaining life?
The troposphere, because it contains most of the air, water vapor, and supports life processes
Why is reducing consumption considered more effective for sustainability than recycling
Because it prevents waste generation entirely, saving energy, raw materials, and reducing emissions across the production chain
Which international agreement aims to limit global temperature rise to below 2°C above pre-industrial levels?
The Paris Agreement
What does the term “keystone species” mean, and can you name one example?
A keystone species is one that has a disproportionately large effect on its ecosystem — if removed, the ecosystem could collapse.
Examples: Sea otters, bees, or wolves.
What is the process by which toxic substances build up in organisms higher up the food chain?
Biomagnification