Answer:
Ocean acidification is often called global warming's evil twin. ... As humans burn more and more fossil fuels, the concentration of carbon dioxide in our atmosphere continues to rise, driving climate change and making both air and sea temperatures hotter and hotter.
The greenhouse effect i think
Answer:
A geographic studying an ecosystem would look at:
- the relationships between human activity and natural systems
- where things are located on the surface of the earth
- why they are located where they are
- how places differ from one another, and how people interact with the environment
It’s about 7.7 billion people to my knowledge, but I would say D, just because when the test you were taking or book you’re looking at was written there was probably less people on Earth