A scientist has a house just beside a busy highway. He collects leaves from some plants growing in his garden to do radio-carbon dating ( to estimate the age of the plant by estimating the amount of a radioisotope of carbon in its tissues ). Surprisingly the radio-carbon dating shows that the plant is a few thousand years old.
(a) Was the result of the radio-carbon dating wrong or can you propose a reason for such an observation ?
(b) What simple experiment can be done to test the reason that you have proposed ?