1. describe at least two things people can do today to protect earth and reduce levels of co2.

- Make climate-conscious political decisions.
- Purchase and use renewable energy sources (natural gas, solar panels etc).
- Try not to leave lights on, fans running, powerpoints on etc when not in use.
- Make sure your house is well insulated.
- Walk, cycle, or take public transport whenever possible. 
- Recycle and reuse materials when possible. Reduce waste going to landfill.
- Buy local produce.
- Buy energy efficient appliances like dishwashers and washing machines.
Hope this helps!
Zoe

Because a model would make the investigation easier to understand

The mass has escaped into a gas which you can not see so the law stays true.