Quantitative and systemic data
The answer would be 25%
Carbon 14 is radioactive material with 5700 year of half-time which will change it into carbon-12, a more stable substance. If the age of the fossil is 11,400 years old, then the amount of half-time passed would be: 11,400 years/ (5,700years/ half-time)= 2 half-time.
Since it undergo 2 half-time, the percentage should be: 100% * (1/2)^2= 25%
Some of these can easily be eliminated by knowing that both nitrogen 14 and nitrogen 15 are isotopes ( same element, with the same amount of protons, but with different numbers of neutrons) of nitrogen. So if the only difference between nitrogen 14, 15 , and regular nitrogen is the amount of neutrons...how many protons and electrons should both nitrogen 14 and 15 have? After thinking, you should be able to eliminate A, B,and C.
