Answer:
B.) In the air, only oxygen is part of the system.
Explanation:
Data given:
Robbie: 15% more than Rebecca:220 movies, which is 10% more than Joshua
Robbie=?
Joshua=?
Solution:
Robbie:
220+(220/10+220/5)=220+(22+11)=253 movies
Joshua:
220-(220/10)=220-22=198 movies
hydrogen and oxygen
H2O