1. Why has the percentage of hydrogen decreased from the early atmosphere to now?
- It's escaped from the atompshere
- It dissolved in oceans and rivers
- It has been trapped underground
- Human activity
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Other questions in this quiz
2. Which one of these processes increases carbon dioxide levels?
- Nitrogen Fixation
- Dissolution in the oceans
- Volcanic Activity
3. How does nitrogen support life?
- Used as nutrients for plants
- Blocks harmful UV rays
- Used in photosynthesis
- Used in respiration
4. Why do carbon dioxide levels rise at night?
- Plants photosynthesise less
- Plants don't photosynthesise
- Humans breathe more
- Increased burning of fossil fuels
5. Why does the rate of photosynthesis increase in the summer?
- Longer day hours and hotter weather
- Shorter day hours and hotter weather
- Longer day hours and increased rainfall
- Shorter day hours and decreased rainfall