Which Is TRUE of the Amount of CO₂ in Our

Multiple Choice

Which is TRUE of the amount of CO₂ in our atmosphere?

A) The level of CO₂ increased at the rate of 1.1% per year from 1990 to 1999.
B) The level of CO₂ has been decreasing at the rate of 3.1% per year since 2000.
C) CO₂ is the most abundant gas in the atmosphere.
D) The level of CO₂ has been much higher during the past 800,000 years than it is now.