How have scientists used isotopic analysis to determine the rise of atmospheric CO2 is mostly from the burning of fossil fuels?
A)Since 14C is an unstable isotope,scientists have dated the atmospheric carbon to the period since the Industrial Revolution.
B)Both coal and oil contain a high proportion of 14C.By analyzing,14C /12C ratios,scientists have been able to determine the source based on this fact.
C)The low proportions of 13C and 14C within atmospheric CO2 indicates the source is fossil carbon.
D)14C concentrations are much higher in urban areas than in rural areas,indicating fossil fuels must have a higher 14C /12C ratio than carbon from other sources.
E)The relative low amount of 12C in atmospheric carbon demonstrates that the carbon dates from about the 1800s or later.

Question

Quizplus · Accepted Answer

Fossil fuels, which are millions of years old, have virtually no 14C due to its half-life. The burning of fossil fuels releases CO2 with a lower 13C/12C ratio compared to the atmosphere, and the absence of 14C, indicating the source is ancient carbon, not recent biological activity.

How Have Scientists Used Isotopic Analysis to Determine the Rise