Which is true of the level of C in our atmosphere?
A) It is reached 400 ppm in 2013.
B) The rate of increase leveled out in 1976.
C) The level of C was much higher in 1955 than today.
D) The level of C is decreasing at 3.1% per year.

Question

Which is true of the level of C  in our atmosphere?
A) It is reached 400 ppm in 2013. 
B) The rate of increase leveled out in 1976. 
C) The level of C was much higher in 1955 than today. 
D) The level of C is decreasing at 3.1% per year.

Quizplus · Accepted Answer

The level of C 11ea3efb_46ef_1b44_920e_cf294112d306_TB3272_11 in our atmosphere reached 400 ppm in 2013, which is the highest level in at least the past 800,000 years. B is incorrect as the rate of increase has not leveled out, and C and D are both incorrect as they are not supported by evidence.

Which Is True of the Level of C in Our