I believe the answer is A, but Im not 100% I hope this helps!
Answer: Bassically, certain gasses like CO2 (Carbon Dioxide) that come from stuff like burning fossil fuels and global warming, they heat up the earth, are wastes and are used as fuel.
1 and 2 because its nature
1. School on weekends 2x a month
2. 16 hour work days
3. Students clean the school after each day instead of janitors
There are 7 characteristics of Egypt.
1.Stable food supply
2.social structure
3.government
4.religion
5.culture
6.written language
7.technology.
